[gvfs] (8 commits) ...google: Handle child of volatile also as volatile

[Ondrej Holy <oholy src gnome org>]

Summary of changes:

  a23901a... google: Move debug prints before releasing entry (*)
  2714228... google: Remove also dir_collisions entries (*)
  014a3d9... google: Ignore entries without parents (*)
  7e45f20... google: Add support for files with multiple parents (*)
  7d55772... google: Remove file just from concrete parent (*)
  6e6d30d... google: Rework cache for better performance (*)
  649254c... google: Use cache for enumeration also (*)
  7a1c184... google: Handle child of volatile also as volatile (*)

(*) This commit already existed in another branch; no separate mail sent