Medium: fs-lib.sh: Faster filesystem start/stop through use of 'findmnt' command for 'is_mounted' function

Resolves: rhbz#919231
Resolves: rhbz#851188
Merge pull request #257 from davidvossel/faster_mounts

Medium: fs-lib.sh: Faster filesystem start/monitor/stop through use of 'findmnt' cli tool