block: include original filename when reporting invalid URIs

Consider passing a JSON based block driver to "qemu-img commit"

$ qemu-img commit 'json:{"driver":"qcow2","file":{"driver":"gluster",\
                  "volume":"gv0","path":"sn1.qcow2",
                  "server":[{"type":\
		  "tcp","host":"10.73.199.197","port":"24007"}]},}'

Currently it will commit the content and then report an incredibly
useless error message when trying to re-open the committed image:

  qemu-img: invalid URI
  Usage: file=gluster[+transport]://[host[:port]]volume/path[?socket=...][,file.debug=N][,file.logfile=/path/filename.log]

With this fix we get:

  qemu-img: invalid URI json:{"server.0.host": "10.73.199.197",
      "driver": "gluster", "path": "luks.qcow2", "server.0.type":
      "tcp", "server.0.port": "24007", "volume": "gv0"}

Of course the root cause problem still exists, but now we know
what actually needs fixing.

Signed-off-by: Daniel P. Berrangé <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Message-id: [email protected]
Signed-off-by: Jeff Cody <[email protected]>

block/gluster.c

@@ -665,7 +665,7 @@ static int qemu_gluster_parse(BlockdevOptionsGluster *gconf,
     if (filename) {
         ret = qemu_gluster_parse_uri(gconf, filename);
         if (ret < 0) {
-            error_setg(errp, "invalid URI");
+            error_setg(errp, "invalid URI %s", filename);
             error_append_hint(errp, "Usage: file=gluster[+transport]://"
                                     "[host[:port]]volume/path[?socket=...]"
                                     "[,file.debug=N]"

block/sheepdog.c

@@ -1036,7 +1036,7 @@ static void sd_parse_uri(SheepdogConfig *cfg, const char *filename,
 
     cfg->uri = uri = uri_parse(filename);
     if (!uri) {
-        error_setg(&err, "invalid URI");
+        error_setg(&err, "invalid URI '%s'", filename);
         goto out;
     }