remove duplicate "text_repository_usernames_mapping" from Lithuanian translation

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11699 e93f8b46-1217-0410-a6f0-8f06a7374b81
Lithuanian translation for 2.3-stable updated by Vasaris Vėjas (#13678, #13674)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11700 e93f8b46-1217-0410-a6f0-8f06a7374b81