Backported r10842 from trunk.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/2.1-stable@11150 e93f8b46-1217-0410-a6f0-8f06a7374b81
Upgrade to Rails 3.2.11.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/2.1-stable@11151 e93f8b46-1217-0410-a6f0-8f06a7374b81
Changes for 2.1.6 release.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/2.1-stable@11152 e93f8b46-1217-0410-a6f0-8f06a7374b81