git-svn: cleanup remove unused function
git-svn: cleanup remove unused function

Also move tz_to_s_offset into Git::SVN::Log since that's
the only place it's used now.

Signed-off-by: Eric Wong <8c2951295f8292b0c03727bc4652981172298eae@yhbt.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git