serve: rename is_command() to parse_command()

The is_command() function not only tells us whether the pktline is a
valid command string, but it also parses out the command (and complains
if we see a duplicate). Let's rename it to make those extra functions
a bit more obvious.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

serve.c

@@ -163,7 +163,7 @@ static int is_valid_capability(const char *key)
 	return c && c->advertise(the_repository, NULL);
 }
 
-static int is_command(const char *key, struct protocol_capability **command)
+static int parse_command(const char *key, struct protocol_capability **command)
 {
 	const char *out;
 
@@ -251,7 +251,7 @@ static int process_request(void)
 			BUG("Should have already died when seeing EOF");
 		case PACKET_READ_NORMAL:
 			/* collect request; a sequence of keys and values */
-			if (is_command(reader.line, &command) ||
+			if (parse_command(reader.line, &command) ||
 			    is_valid_capability(reader.line))
 				strvec_push(&keys, reader.line);
 			else