connect.c: refactor sending of agent & object-format

Refactor the sending of the "agent" and "object-format" capabilities
into a function.

This was added in its current form in ab67235bc4 (connect: parse v2
refs with correct hash algorithm, 2020-05-25). When we connect to a v2
server we need to know about its object-format, and it needs to know
about ours. Since most things in connect.c and transport.c piggy-back
on the eager getting of remote refs via the handshake() those commands
can make use of the just-sent-over object-format by ls-refs.

But I'm about to add a command that may come after ls-refs, and may
not, but we need the server to know about our user-agent and
object-format. So let's split this into a function.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

connect.c

@@ -473,22 +473,9 @@ void check_stateless_delimiter(int stateless_rpc,
 		die("%s", error);
 }
 
-struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
-			     struct ref **list, int for_push,
-			     struct transport_ls_refs_options *transport_options,
-			     const struct string_list *server_options,
-			     int stateless_rpc)
+static void send_capabilities(int fd_out, struct packet_reader *reader)
 {
-	int i;
 	const char *hash_name;
-	struct strvec *ref_prefixes = transport_options ?
-		&transport_options->ref_prefixes : NULL;
-	const char **unborn_head_target = transport_options ?
-		&transport_options->unborn_head_target : NULL;
-	*list = NULL;
-
-	if (server_supports_v2("ls-refs", 1))
-		packet_write_fmt(fd_out, "command=ls-refs\n");
 
 	if (server_supports_v2("agent", 0))
 		packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
@@ -502,6 +489,26 @@ struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 	} else {
 		reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 	}
+}
+
+struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
+			     struct ref **list, int for_push,
+			     struct transport_ls_refs_options *transport_options,
+			     const struct string_list *server_options,
+			     int stateless_rpc)
+{
+	int i;
+	struct strvec *ref_prefixes = transport_options ?
+		&transport_options->ref_prefixes : NULL;
+	const char **unborn_head_target = transport_options ?
+		&transport_options->unborn_head_target : NULL;
+	*list = NULL;
+
+	if (server_supports_v2("ls-refs", 1))
+		packet_write_fmt(fd_out, "command=ls-refs\n");
+
+	/* Send capabilities */
+	send_capabilities(fd_out, reader);
 
 	if (server_options && server_options->nr &&
 	    server_supports_v2("server-option", 1))