Add allocation and freeing functions for struct refs

Instead of open-coding allocation wherever it happens, have a function.
Also, add a function to free a list of refs, which we currently never
actually do.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote.h

@@ -30,6 +30,13 @@ struct refspec {
 	char *dst;
 };
 
+struct ref *alloc_ref(unsigned namelen);
+
+/*
+ * Frees the entire list and peers of elements.
+ */
+void free_refs(struct ref *ref);
+
 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 	       int nr_refspec, char **refspec, int all);