Rails4: fix time related git adapter test failures

git-svn-id: http://svn.redmine.org/redmine/trunk@12882 e93f8b46-1217-0410-a6f0-8f06a7374b81
use escaped "Can't" constant at MailerTest

git-svn-id: http://svn.redmine.org/redmine/trunk@12883 e93f8b46-1217-0410-a6f0-8f06a7374b81