python: improve get/set_lvb documentation
- Specify lvb=True explicitly instead of mentioning the sanlock flag
- Document when data is written and visible
- Unify whitespace in function documentation, consistent with other
functions.
Signed-off-by: Benny Zlotnik <bzlotnik@redhat.com>
Signed-off-by: Nir Soffer <nsoffer@redhat.com>