LU-1279 utils: mount.lustre load ptlrpc module if necessary

LU-1279 utils: mount.lustre load ptlrpc module if necessary

When LNET modules have not loaded, and mounting multiple targets at
the same time could fail. Use mount.lustre to load the network modules
if necessary.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: I9d7a4007cc5b233055a4a985237b01ff0874cf54
Reviewed-on: http://review.whamcloud.com/4292
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>