staging/lustre/obdclass: runtime load lustre client when needed

Manually force loading of lustre.ko during client
mounts with request_module for cases where
autoloading doesn't happen.

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-on: http://review.whamcloud.com/10587
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4800


Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>