fetch: do not redundantly calculate tag refmap

builtin/fetch.c redundantly calculates refmaps for tags twice. Remove
the first calculation.

This is only a code simplification and slight performance improvement -
the result is unchanged, as the redundant refmaps are subsequently
removed by the invocation to "ref_remove_duplicates" anyway.

This was introduced in commit c5a84e9 ("fetch --tags: fetch tags *in
addition to* other stuff", 2013-10-29) when modifying the effect of the
--tags parameter to "git fetch". The refmap-for-tag calculation was
copied instead of moved.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fetch.c

@@ -347,9 +347,6 @@ static struct ref *get_ref_map(struct transport *transport,
 
 		for (i = 0; i < fetch_refspec_nr; i++)
 			get_fetch_map(ref_map, &fetch_refspec[i], &oref_tail, 1);
-
-		if (tags == TAGS_SET)
-			get_fetch_map(remote_refs, tag_refspec, &tail, 0);
 	} else if (refmap_array) {
 		die("--refmap option is only meaningful with command-line refspec(s).");
 	} else {