cvsimport: have default merge regex also match beginning of commit message

The default value of @mergerx uses \W, which matches a non-word
character; this means that commit messages like "Merging FOO" are not
matched by default; using \b, which matches a word boundary, instead of
\W fixes that.

This change was suggested by Frédéric Brière through
 http://bugs.debian.org/463468Signed-off-by: NGerrit Pape <pape@smarden.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-cvsimport.perl

@@ -164,7 +164,7 @@ sub read_repo_config {
 
 our @mergerx = ();
 if ($opt_m) {
-	@mergerx = ( qr/\W(?:from|of|merge|merging|merged) (\w+)/i );
+	@mergerx = ( qr/\b(?:from|of|merge|merging|merged) (\w+)/i );
 }
 if ($opt_M) {
 	push (@mergerx, qr/$opt_M/);