flapjack omnibus build can't find rake (changes: ruby 1.9.3 -> 2.1.1; removing Gemfile.lock before bundle install)

gistfile1.txt

      [Builder: flapjack] I | Executing: `/opt/flapjack/embedded/bin/bundle exec rake build` with cwd=/var/cache/omnibus/src/flapjack,timeout=5400,live_stream=#<Omnibus::Logger::LiveStream:0x00000001c6ef98>,env="RUBYOPT= BUNDLE_BIN_PATH= BUNDLE_GEMFILE= GEM_PATH= GEM_HOME="
      [Builder: flapjack] W | /opt/flapjack/embedded/bin/bundle command failed! (0.4823312s)
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Failed to build flapjack while running `/opt/flapjack/embedded/bin/bundle exec rake build` with cwd=/var/cache/omnibus/src/flapjack,timeout=5400,live_stream=#<Omnibus::Logger::LiveStream:0x00000001c6ef98>,env="RUBYOPT= BUNDLE_BIN_PATH= BUNDLE_GEMFILE= GEM_PATH= GEM_HOME="
Exception:
  Mixlib::ShellOut::ShellCommandFailed: Expected process to exit with [0], but received '1'
  ---- Begin output of /opt/flapjack/embedded/bin/bundle exec rake build ----
  STDOUT:
  STDERR: /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/spec_set.rb:92:in `block in materialize': Could not find rake-10.3.2 in any of the sources (Bundler::GemNotFound)
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/spec_set.rb:85:in `map!'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/spec_set.rb:85:in `materialize'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/definition.rb:133:in `specs'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/definition.rb:178:in `specs_for'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/definition.rb:167:in `requested_specs'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/environment.rb:18:in `requested_specs'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/runtime.rb:13:in `setup'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler.rb:120:in `setup'
  	from /var/lib/gems/1.9.1/gems/bundler-1.6.3/lib/bundler/setup.rb:17:in `<top (required)>'
  	from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
  	from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
  ---- End output of /opt/flapjack/embedded/bin/bundle exec rake build ----
  Ran /opt/flapjack/embedded/bin/bundle exec rake build returned 1
    /var/lib/gems/1.9.1/gems/mixlib-shellout-1.4.0/lib/mixlib/shellout.rb:257:in `invalid!'
    /var/lib/gems/1.9.1/gems/mixlib-shellout-1.4.0/lib/mixlib/shellout.rb:244:in `error!'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:277:in `block in execute_sh'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:327:in `time_it'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:275:in `execute_sh'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:233:in `execute'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:223:in `block (2 levels) in build'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:222:in `each'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:222:in `block in build'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:327:in `time_it'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/builder.rb:221:in `build'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/software.rb:621:in `execute_build'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/software.rb:451:in `build_me'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/project.rb:95:in `block in build_me'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/project.rb:94:in `each'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/project.rb:94:in `build_me'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/cli.rb:72:in `build'
    /var/lib/gems/1.9.1/gems/thor-0.19.1/lib/thor/command.rb:27:in `run'
    /var/lib/gems/1.9.1/gems/thor-0.19.1/lib/thor/invocation.rb:126:in `invoke_command'
    /var/lib/gems/1.9.1/gems/thor-0.19.1/lib/thor.rb:359:in `dispatch'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/cli/base.rb:33:in `dispatch'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/cli/deprecated.rb:128:in `dispatch'
    /var/lib/gems/1.9.1/gems/thor-0.19.1/lib/thor/base.rb:440:in `start'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/lib/omnibus/cli.rb:41:in `execute!'
    /var/lib/gems/1.9.1/bundler/gems/omnibus-ruby-5ad405c915e4/bin/omnibus:11:in `<top (required)>'
    bin/omnibus:16:in `load'
    bin/omnibus:16:in `<main>'
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