Replicates gh-pages rubygem issue [#280](https://github.com/github/pages-gem/issues/280).

pages bug full replication

Versions:

```
$ jekyll -v
    jekyll 3.0.4
$ bundle -v
    Bundler version 1.11.2
$ ruby --version
    ruby 2.1.7p400 (2015-08-18 revision 51632) [x86_64-linux]
```

Project initialization:

```
$ git init testJekyll
    Initialized empty Git repository in /home/kdbanman/dev/testJekyll/.git/
$ cd testJekyll/
$ git remote add origin [email protected]:kdbanman/testJekyll.git
$ printf "source 'https://rubygems.org'\ngem 'github-pages', group: :jekyll_plugins" > Gemfile
$ bundle install
    Fetching gem metadata from https://rubygems.org/............
    Fetching version metadata from https://rubygems.org/...
    Fetching dependency metadata from https://rubygems.org/..
    Resolving dependencies....
    Using RedCloth 4.2.9
    Using i18n 0.7.0
    Using json 1.8.3
    Using minitest 5.8.4
    Using thread_safe 0.3.5
    Using addressable 2.4.0
    Using coffee-script-source 1.10.0
    Using execjs 2.6.0
    Using colorator 0.1
    Using ffi 1.9.10
    Using multipart-post 2.0.0
    Using gemoji 2.1.0
    Using net-dns 0.8.0
    Using public_suffix 1.5.3
    Using sass 3.4.22
    Using rb-fsevent 0.9.7
    Using kramdown 1.10.0
    Using liquid 3.0.6
    Using mercenary 0.3.6
    Using rouge 1.10.1
    Using safe_yaml 1.0.4
    Using jekyll-feed 0.5.1
    Using mini_portile2 2.0.0
    Using jekyll-paginate 1.1.0
    Using jekyll-sitemap 0.10.0
    Using rdiscount 2.1.8
    Using redcarpet 3.3.3
    Using terminal-table 1.5.2
    Using bundler 1.11.2
    Using jekyll-textile-converter 0.1.0
    Using tzinfo 1.2.2
    Using coffee-script 2.4.1
    Using ethon 0.8.1
    Using rb-inotify 0.9.7
    Using faraday 0.9.2
    Using jekyll-sass-converter 1.3.0
    Using nokogiri 1.6.7.2
    Using activesupport 4.2.6
    Using jekyll-coffeescript 1.0.1
    Using typhoeus 0.8.0
    Using listen 3.0.6
    Using sawyer 0.7.0
    Using html-pipeline 2.4.0
    Installing jekyll-watch 1.4.0
    Using octokit 4.3.0
    Using jekyll 3.0.4
    Using github-pages-health-check 1.1.0
    Using jekyll-gist 1.4.0
    Using jekyll-github-metadata 1.11.1
    Using jekyll-mentions 1.1.2
    Using jekyll-redirect-from 0.10.0
    Using jekyll-seo-tag 1.3.3
    Using jemoji 0.6.2
    Installing github-pages 75
    Bundle complete! 1 Gemfile dependency, 54 gems now installed.
    Use `bundle show [gemname]` to see where a bundled gem is installed.
    Post-install message from github-pages:
    ---------------------------------------------------
    Thank you for installing github-pages!
    GitHub Pages recently upgraded to Jekyll 3.0, which
    includes some breaking changes. More information:
    https://github.com/blog/2100-github-pages-jekyll-3
    ---------------------------------------------------
```

Now generate the site and serve it:

```
$ bundle exec jekyll new . --force
    New jekyll site installed in /home/kdbanman/dev/testJekyll
$ bundle exec jekyll serve
    Configuration file: /home/kdbanman/dev/testJekyll/_config.yml
           Deprecation: Auto-regeneration can no longer be set from your configuration file(s). Use the --[no-]watch/-w command-line option instead.
                Source: /home/kdbanman/dev/testJekyll
           Destination: /home/kdbanman/dev/testJekyll/_site
     Incremental build: disabled. Enable with --incremental
          Generating... 
                        done in 0.354 seconds.
     Auto-regeneration: disabled. Use --watch to enable.
    Configuration file: /home/kdbanman/dev/testJekyll/_config.yml
           Deprecation: Auto-regeneration can no longer be set from your configuration file(s). Use the --[no-]watch/-w command-line option instead.
        Server address: http://127.0.0.1:4000/
      Server running... press ctrl-c to stop.
```

And notice that **the `-w` switch is ignored**:

```
$ bundle exec jekyll serve -w
    Configuration file: /home/kdbanman/dev/testJekyll/_config.yml
           Deprecation: Auto-regeneration can no longer be set from your configuration file(s). Use the --[no-]watch/-w command-line option instead.
                Source: /home/kdbanman/dev/testJekyll
           Destination: /home/kdbanman/dev/testJekyll/_site
     Incremental build: disabled. Enable with --incremental
          Generating... 
                        done in 0.362 seconds.

     Auto-regeneration: disabled. Use --watch to enable.  
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    Configuration file: /home/kdbanman/dev/testJekyll/_config.yml
           Deprecation: Auto-regeneration can no longer be set from your configuration file(s). Use the --[no-]watch/-w command-line option instead.
        Server address: http://127.0.0.1:4000/
      Server running... press ctrl-c to stop.
```

(Emphasis is my own.)