LU-3185 build: fix autogen with modern autoconf tools

LU-3185 build: fix autogen with modern autoconf tools

Modern autoconf tools request configure scripts to be more
strict in style, some fixes to improve autoconf usage.

Signed-off-by: Alexey Lyashkov <alexey_lyashkov@xyratex.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I954c0fc7be34d84ec279883debc44e7a543ebbe5
Reviewed-on: http://review.whamcloud.com/7490
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Tested-by: Hudson
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>