LU-6215 ldlm: handle percpu_counter_init change in 3.18+ kernels

LU-6215 ldlm: handle percpu_counter_init change in 3.18+ kernels

Starting in 3.18 kernels the function percpu_counter_init()
started to take memory allocation flags GFP_*. This patch
detects and handles this new case thus enabling lustre servers
to function up to 4.2.1 kernels.

Change-Id: Ibdb716987c367dc6ea93f6f9747fb70fd7ac2cbb
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: http://review.whamcloud.com/16649
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Reviewed-by: Frank Zago <fzago@cray.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>