drop "match" parameter from get_remote_heads

The get_remote_heads function reads the list of remote refs
during git protocol session. It dates all the way back to
def88e9 (Commit first cut at "git-fetch-pack", 2005-07-04).
At that time, the idea was to come up with a list of refs we
were interested in, and then filter the list as we got it
from the remote side.

Later, 1baaae5 (Make maximal use of the remote refs,
2005-10-28) stopped filtering at the get_remote_heads layer,
letting us use the non-matching refs to find common history.

As a result, all callers now simply pass an empty match
list (and any future callers will want to do the same). So
let's drop these now-useless parameters.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fetch-pack.c

@@ -976,7 +976,7 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 				   args.verbose ? CONNECT_VERBOSE : 0);
 	}
 
-	get_remote_heads(fd[0], &ref, 0, NULL, 0, NULL);
+	get_remote_heads(fd[0], &ref, 0, NULL);
 
 	ref = fetch_pack(&args, fd, conn, ref, dest,
 		nr_heads, heads, pack_lockfile_ptr);