Preserve git committer in dcommit

When dcommiting the latest changes in the git repository to svn, the username of the dcommitter is used, and no trace of the user who originally committed the change to git is forwarded. Using the git-svn option --add-author-from seems to partly solve the issue:

When committing to svn from git (as part of commit-diff, set-tree or dcommit operations), if the existing log message doesn't already have a From: or Signed-off-by: line, append a From: line based on the git commit's author string. If you use this, then --use-log-author will retrieve a valid author string for all commits.

References:

• The git-svn manual
• git svn dcommit with svn usernames on stackoverflow.