Tweak the RE used to parse make dump-vars output.

This fixes the annoying problem with REVISIONs not being added for ports
that have default FLAVOR other than "" (empty one).

Brought to my eyes by jeremy@, initial ideas from him and afresh1@.

infrastructure/bin/portbump

@@ -82,7 +82,7 @@ sub new {
 		die "cannot run make dump-vars";
 	while (<$dumpvars>) {
 		chomp;
-		next unless /^[^,]*(?:,(-[^.]+))?\.([^=.]+)=(.*)$/;
+		next unless /^[^,]*(?:,[^.-]*(-[^.]+)?)?\.([^=.]+)=(.*)$/;
 		my ($subpkg, $var, $value) = ($1, $2, $3);
 		$subpkg //= "";