Under Debian `e2fsck` is found in `/sbin/` which does not match the
existing "version" the script currently uses (`/usr/sbin/e2fsck`
versus `/sbin/e2fsck`); therefore I added a simple `if` condition to
remedy the situation by verifying whether the original path exists or
not, so I can use the one Debian expects.
Special thanks goes to Tim Flynn a.k.a. `trflynn89` for his valuable
feedback.