refspec: convert valid_fetch_refspec to use parse_refspec

Convert 'valid_fetch_refspec()' to use the new 'parse_refspec()'
function to only parse a single refspec and eliminate an allocation.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refspec.c

@@ -146,15 +146,6 @@ static struct refspec_item *parse_refspec_internal(int nr_refspec, const char **
 	die("Invalid refspec '%s'", refspec[i]);
 }
 
-int valid_fetch_refspec(const char *fetch_refspec_str)
-{
-	struct refspec_item *refspec;
-
-	refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
-	free_refspec(1, refspec);
-	return !!refspec;
-}
-
 struct refspec_item *parse_fetch_refspec(int nr_refspec, const char **refspec)
 {
 	return parse_refspec_internal(nr_refspec, refspec, 1, 0);
@@ -242,3 +233,11 @@ void refspec_clear(struct refspec *rs)
 
 	rs->fetch = 0;
 }
+
+int valid_fetch_refspec(const char *fetch_refspec_str)
+{
+	struct refspec_item refspec;
+	int ret = parse_refspec(&refspec, fetch_refspec_str, REFSPEC_FETCH);
+	refspec_item_clear(&refspec);
+	return ret;
+}

refspec.h

@@ -14,7 +14,6 @@ struct refspec_item {
 	char *dst;
 };
 
-int valid_fetch_refspec(const char *refspec);
 struct refspec_item *parse_fetch_refspec(int nr_refspec, const char **refspec);
 struct refspec_item *parse_push_refspec(int nr_refspec, const char **refspec);
 
@@ -45,4 +44,6 @@ void refspec_append(struct refspec *rs, const char *refspec);
 void refspec_appendn(struct refspec *rs, const char **refspecs, int nr);
 void refspec_clear(struct refspec *rs);
 
+int valid_fetch_refspec(const char *refspec);
+
 #endif /* REFSPEC_H */