LU-10185 gnilnd: Add mod param to adjust vmalloc's retry flag

LU-10185 gnilnd: Add mod param to adjust vmalloc's retry flag

In kernel 3.12 gnilnd had issues with the memory allocator
getting stuck trying to find pages for long periods of time
so __GFP_NORETRY was added to fail fast. The memory subsystem
has changed enough that it is beleived that vmalloc will fail
if it can't get pages.

Add modparam to allow no_retry flag to be enabled or disabled
dynamically.

Test-parameters: trivial

Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I067a8d7b52d237e464fceae7e2220f2488b68957
Reviewed-on: https://review.whamcloud.com/29894
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Shimek <knathrak@gmail.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Doug Oucharek <dougso@me.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>