azureblob: fix "Entry doesn't belong in directory" errors when using …

…directory markers

Before this change we were incorrectly identifying the root directory
of the listing and adding it into the listing.

This caused higher layers of rclone to emit the error above.

See rclone#7038

backend/azureblob/azureblob.go

@@ -1063,11 +1063,7 @@ func (f *Fs) list(ctx context.Context, containerName, directory, prefix string,
 				fs.Debugf(f, "Odd name received %q", remote)
 				continue
 			}
-			remote = remote[len(prefix):]
 			isDirectory := isDirectoryMarker(*file.Properties.ContentLength, file.Metadata, remote)
-			if addContainer {
-				remote = path.Join(containerName, remote)
-			}
 			if isDirectory {
 				// Don't insert the root directory
 				if remote == directory {
@@ -1076,6 +1072,10 @@ func (f *Fs) list(ctx context.Context, containerName, directory, prefix string,
 				// process directory markers as directories
 				remote = strings.TrimRight(remote, "/")
 			}
+			remote = remote[len(prefix):]
+			if addContainer {
+				remote = path.Join(containerName, remote)
+			}
 			// Send object
 			err = fn(remote, file, isDirectory)
 			if err != nil {