LU-7555 tests: add load_module to mount_facet

LU-7555 tests: add load_module to mount_facet

Since commit 2a223541d299bc8 there has not been automated loading
of lustre modules in the log() command, since this command only
needs libcfs loaded to use the "lctl mark" functionality.

When testing from a local build tree, conf-sanity.sh was failing
because it unloads the modules during cleanup and is not able to
automatically load the modules on demand if they are not installed,
and does not always manually load the modules for each running test.

Add a call to load_modules() in mount_facet() where the modules are
actually needed for the filesystem to mount.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Ie7655c04a7bf42ec9969cb5c11fab3ac92f3dc0b
Reviewed-on: http://review.whamcloud.com/17603
Reviewed-by: Jian Yu <jian.yu@intel.com>
Tested-by: Jenkins
Reviewed-by: wangdi <di.wang@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Wei Liu <wei3.liu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>