scm: git: change non ASCII user name variable to instance variable (#14931)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@12142 e93f8b46-1217-0410-a6f0-8f06a7374b81
scm: git: use "--encoding=UTF-8" for blame (#14931)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@12143 e93f8b46-1217-0410-a6f0-8f06a7374b81