Account the nr_entries in rblist properly

The nr_entries in rblist is never decremented when an element
is deleted. Also, use rblist__remove_node to delete a node in
rblist__delete(). This would keep the nr_entries sane.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Acked-by: David S. Ahern <dsahern@gmail.com>
Cc: David S. Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/20120831070834.14806.87398.stgit@suzukikp.in.ibm.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>