Revert "upload-pack: send non-HEAD symbolic refs"

This reverts commit 5e7dcad771cb873e278a0571b46910d7c32e2f6c; there
may be unbounded number of symbolic refs in the repository, but the
capability header line in the on-wire protocol has a rather low
length limit.

upload-pack.c

diff --git a/upload-pack.c b/upload-pack.c
index fd96f3b..a020d30 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -752,7 +752,6 @@
 	struct string_list symref = STRING_LIST_INIT_DUP;
 
 	head_ref_namespaced(find_symref, &symref);
-	for_each_namespaced_ref(find_symref, &symref);
 
 	if (advertise_refs || !stateless_rpc) {
 		reset_timeout();