git-cvsexportcommit: don't cleanup .msg if not yet committed to cvs.

Unless the -c option is given, and the commit to cvs was successful,
.msg shouldn't be deleted to be able to run the command suggested by
git-cvsexportcommit.

See http://bugs.debian.org/412732

Signed-off-by: Gerrit Pape <pape@smarden.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-cvsexportcommit.perl

@@ -241,13 +241,14 @@
 	die "Exiting: The commit did not succeed";
     }
     print "Committed successfully to CVS\n";
+    # clean up
+    unlink(".msg");
 } else {
     print "Ready for you to commit, just run:\n\n   $cmd\n";
 }
 
 # clean up
 unlink(".cvsexportcommit.diff");
-unlink(".msg");
 
 sub usage {
 	print STDERR <<END;