LU-5971 llite: merge lclient.h into llite/vvp_internal.h

LU-5971 llite: merge lclient.h into llite/vvp_internal.h

Move the definition of struct cl_client_cache to
lustre/include/cl_object.h and move the rest of
lustre/include/lclient.h in to lustre/llite/vvp_internal.h.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ib3ca8f1693c517a77c5bfd7c7cced9bfc440c747
Reviewed-on: http://review.whamcloud.com/12592
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>