qemuDomainBuildNamespace: Try harder to remove temp directories

If building namespace fails somewhere in the middle (that is some
files exists under devMountsSavePath[i]), then plain rmdir() is
not enough to remove dir. Umount the temp location and use
virFileDeleteTree() to remove the directory.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NPavel Mores <pmores@redhat.com>

src/qemu/qemu_domain.c

@@ -15311,9 +15311,12 @@ qemuDomainBuildNamespace(virQEMUDriverConfigPtr cfg,
     ret = 0;
  cleanup:
     for (i = 0; i < ndevMountsPath; i++) {
+#if defined(__linux__)
+        umount(devMountsSavePath[i]);
+#endif /* defined(__linux__) */
         /* The path can be either a regular file or a dir. */
         if (virFileIsDir(devMountsSavePath[i]))
-            rmdir(devMountsSavePath[i]);
+            virFileDeleteTree(devMountsSavePath[i]);
         else
             unlink(devMountsSavePath[i]);
     }