virtio-9p-proxy: improve error messages in connect_namedsocket()

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>

hw/9pfs/virtio-9p-proxy.c

@@ -1104,14 +1104,14 @@ static int connect_namedsocket(const char *path)
 
     sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
     if (sockfd < 0) {
-        fprintf(stderr, "socket %s\n", strerror(errno));
+        fprintf(stderr, "failed to create socket: %s\n", strerror(errno));
         return -1;
     }
     strcpy(helper.sun_path, path);
     helper.sun_family = AF_UNIX;
     size = strlen(helper.sun_path) + sizeof(helper.sun_family);
     if (connect(sockfd, (struct sockaddr *)&helper, size) < 0) {
-        fprintf(stderr, "socket error\n");
+        fprintf(stderr, "failed to connect to %s: %s\n", path, strerror(errno));
         close(sockfd);
         return -1;
     }