LU-336 Tighten matching criteria in module_loaded

LU-336 Tighten matching criteria in module_loaded

The function module_loaded can easily produce false positives because
of it's lenient way of grep'ing the output of lsmod. Tightening up the
criteria upon which it uses to determine if a module is loaded, reduces
the risk of returning these false positives.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Change-Id: Id8a20bf568be275eeb3ef466cb3fd051f8389b44
Reviewed-on: http://review.whamcloud.com/558
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Yu Jian <yujian@whamcloud.com>
Reviewed-by: Brian J. Murrell <brian@whamcloud.com>