git-svn: fix dcommit to urls with embedded usernames

git-svn: fix dcommit to urls with embedded usernames

Don't rely on the extracted URL from working_head_info since that has the
username removed.  Instead use the $gs->full_url method (as before with
ba24e74 (git-svn: add ability to specify --commit-url for dcommit,
2008-08-07)) to give us the URL to commit to if --commit-url is not
specified.

Aditionally, since we clean usernames from URLs, checking the URL after
rebase can fail because it doesn't match the URL we used to commit; so
unconditionally provide a username-free URL for checking the result of the
refetch.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>