Error: Permission denied - /usr/local/Cellar/libiconv/1.14 when running brew upgrade. ==> possible solution

Nokogiri---BrewUpdate Error Fix

Original issue thread here:  https://github.com/sparklemotion/nokogiri/issues/754

I know it's a long time after this issue was closed and I appreciate this is a libiconv / homebrew issue, but just in case others come this way just like me...

In the process of trying to get a zero warnings install of nokogiri on Mac OSX 10.9.3... I had the same problem as @geraldarthur upgrading from libiconv 1.13 to 1.14, namely:
Error: Permission denied - /usr/local/Cellar/libiconv/1.14 when running brew upgrade.
My kludge -
ls -l /usr/local/Cellar/ showed all directories except libiconv owned by me. libiconv owned by root and not otherwise writable. So permission denied not surprising.

$ ls -l /usr/local/Cellar/
total 0
[lines deleted]
drwxr-xr-x  4 rogermarlow  admin  136 16 May 23:51 cmake
drwxr-xr-x  3 rogermarlow  admin  102  7 May 12:07 libgpg-error
drwxr-xr-x  3 root         admin  102 19 Dec  2012 libiconv
drwxr-xr-x  3 rogermarlow  admin  102  7 May 12:07 libksba
[lines deleted]
So, without knowing why it got into this state nor what the consequences of changing it are...
$ sudo chown rogermarlow /usr/local/Cellar/libiconv allows brew upgrade libiconv to complete without error, as does the nokogiri install according to the guidance at http://nokogiri.org/tutorials/installing_nokogiri.html (use all those --with flags)
Revert the ownership of /usr/local/Cellar/libiconv once the install is complete if you are nervous about it.