core: don't close tcp connection for dropped non sip messages

(cherry picked from commit 007f98692bb6f7cb35adbb86ec6fb06f034614cc)

src/core/receive.c

@@ -300,7 +300,7 @@ int receive_msg(char *buf, unsigned int len, receive_info_t *rcv_info)
 			LM_DBG("attempt of nonsip message processing failed\n");
 		} else if(ret == NONSIP_MSG_DROP) {
 			LM_DBG("nonsip message processing completed\n");
-			goto error02;
+			goto end;
 		}
 	}
 	if(errsipmsg==1) {