Add utility function to load and initialize FSAL module

- Utility function: fsal_load_init()
- Call fsal_load_init() in fsal_commit()

Change-Id: I6d4cda982f3758f8d24ccc49a95eb582bb0071de
Signed-off-by: Arun Olappamanna Vasudevan <aolappamanna@cs.stonybrook.edu>
Reviewed-by: Ming Chen <mchen@cs.stonybrook.edu>