LU-10886 build: fix warnings during autoconf

Quiet warnings in configure checks to avoid confusion when debugging
autoconf/configure scripts, and to avoid potential errors during
detection.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I2916a120b57fb9fa529bf7050cf65511233ebbe5
Reviewed-on: https://review.whamcloud.com/31904


Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>