Add committer tag only when needed in git conversion
Convert from a git repo added a committer: tag in the log message
even if the committer and the author were the same person.
changeset: 0:61c9426e69fe
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: test
---- HEADERS
200 Script output follows
---- DATA
[('Content-Type', 'text/html; charset=ascii')]
---- ERRORS