* based on cpython os.path.ismount
* includes patch from http://bugs.python.org/issue2466
* fixes#2186
* when the upstream bug is fixed this should be removed/rewritten
* use ismount from module_utils
Fixes#530.
It's more generic than #578 which only fixes spaces escaping in name (target dir to mount).
Escaping is used in both `set_mount` (important for `src`, `name` and `opts`) and
`unset_mount` (for `name`).
It's shouldn't be used in `mount` and `umount` since `name` parameter is passed as array element
to `module.run_command`.
Signed-off-by: Konstantin Gribov <grossws@gmail.com>