Merged r12143 from trunk to 2.3-stable (#14931)

scm: git: use "--encoding=UTF-8" for blame.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/2.3-stable@12159 e93f8b46-1217-0410-a6f0-8f06a7374b81
Merged r12138, r12149, r12156 and r12157 from trunk to 2.3-stable (#14931)

scm: fix annotate error with non ASCII author on Ruby 1.9 and Ruby 2.0.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/2.3-stable@12160 e93f8b46-1217-0410-a6f0-8f06a7374b81