fix multi_ack.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

connect.c

@@ -8,7 +8,7 @@
 #include <arpa/inet.h>
 #include <netdb.h>
 
-static char *server_capabilities = "";
+static char *server_capabilities = NULL;
 
 /*
  * Read all the refs from the other end
@@ -58,7 +58,8 @@ struct ref **get_remote_heads(int in, struct ref **list,
 
 int server_supports(const char *feature)
 {
-	return strstr(feature, server_capabilities) != NULL;
+	return server_capabilities &&
+		strstr(server_capabilities, feature) != NULL;
 }
 
 int get_ack(int fd, unsigned char *result_sha1)

upload-pack.c

@@ -212,11 +212,15 @@ static int receive_needs(void)
 
 static int send_ref(const char *refname, const unsigned char *sha1)
 {
-	static char *capabilities = "\0multi_ack";
+	static char *capabilities = "multi_ack";
 	struct object *o = parse_object(sha1);
 
-	packet_write(1, "%s %s%s\n", sha1_to_hex(sha1), refname, capabilities);
-	capabilities = "";
+	if (capabilities)
+		packet_write(1, "%s %s%c%s\n", sha1_to_hex(sha1), refname,
+			0, capabilities);
+	else
+		packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname);
+	capabilities = NULL;
 	if (!(o->flags & OUR_REF)) {
 		o->flags |= OUR_REF;
 		nr_our_refs++;