perf: Container and account performance inc

* Container and accounts performance increase by removing
  the need to update either the object count or the
  container count, respectively.  New hidden
  configuratoins added to re-enable the functionality.
* object_only configuratoin removed from fs.conf and
  replaced with a hidden configuration.  The new hidden
  configuration reports gratuituosly crated directories
  as objects, to support a compatibility behavior with
  previous version 1.4.8 (even though it was incorrect).

BUG 988969: https://bugzilla.redhat.com/show_bug.cgi?id=988969

Change-Id: Idca20b8629ec38606ff5692fe62bc2cadabffc86
Signed-off-by: Luis Pabon <lpabon@redhat.com>
Reviewed-on: http://review.gluster.org/5403
Reviewed-by: Peter Portante <pportant@redhat.com>
Tested-by: Peter Portante <pportant@redhat.com>
Reviewed-on: http://review.gluster.org/5504