lib-http: response parser: Drop previous response's pool immediately …

…when parsing continues.

Prevously, it would only do that when the first byte of the next response was received.
This prevents wasting memory when no response is being parsed.

src/lib-http/http-response-parser.c

@@ -146,7 +146,6 @@ static int http_response_parse(struct http_response_parser *parser)
 	 */
 	switch (parser->state) {
 	case HTTP_RESPONSE_PARSE_STATE_INIT:
-		http_response_parser_restart(parser);
 		parser->state = HTTP_RESPONSE_PARSE_STATE_VERSION;
 		/* fall through */
 	case HTTP_RESPONSE_PARSE_STATE_VERSION:
@@ -313,6 +312,9 @@ int http_response_parse_next(struct http_response_parser *parser,
 		return ret;
 	}
 
+	if (parser->state == HTTP_RESPONSE_PARSE_STATE_INIT)
+		http_response_parser_restart(parser);
+
 	/* RFC 7230, Section 3:
 		
 	   HTTP-message   = start-line