LU-9523 obdclass: remove CL_PAGE_INVOKE et. al.

LU-9523 obdclass: remove CL_PAGE_INVOKE et. al.

CL_PAGE_INVOKE, CL_PAGE_INVOID and CL_PAGE_INVOKE_REVERSE
merely obscure the list_for_each_entry calls to various virtual
functions specified by CL_PAGE_OP, and arguments stuck into va_args.

These defines and their equivalent functions have been removed,
and the list_for_each_entry has been put in place.  CL_PAGE_OP
has also been removed.

Signed-off-by: Ben Evans <bevans@cray.com>
Change-Id: I644e707263c2a31c7c2a3d1435248199efb6b274
Reviewed-on: https://review.whamcloud.com/27168
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>