Merged r11980 from trunk to 2.3-stable (#9996)

replace "email.yml" to "configuration.yml" in pl.yml.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/2.3-stable@11981 e93f8b46-1217-0410-a6f0-8f06a7374b81