LU-261 Renamed auster.sh to be auster

LU-261 Renamed auster.sh to be auster

This makes it like b2_1 and following the convention that human commands don't
have extensions and modified Makefile.am which references auster[.sh]
Also remove libcfs from REQUIRED_DIRS in autogen.sh since libcfs is still
under lnet in lustre 1.8.

Change-Id: I29247005a6b02b039cf4a861af4dc5de30082c23
Signed-off-by: Chris Gearing <chris@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/541
Tested-by: Hudson
Reviewed-by: Johann Lombardi <johann@whamcloud.com>