Find the merge parent faster.
* svn-merge2git.sh (find_merge_parent): Generate an ERE that
intelligently matches the possible merge parents so that the first
commit found by rev-list is the merge parent (instead of finding all
the commits in the merged branch and piping this all through a Perl
script that finds the good parent).
(rewrite_history): Make sure that filter-branch does not fail.
(top-level aka `main'): Count the total number of commits processed.
Signed-off-by: Benoit Sigoure <tsuna@lrde.epita.fr>