'del g' is a trap for the unwary. If the handle has any other
references, it does nothing (in fact, it can be actively dangerous if
the user was expecting the appliance to go away). In non-CPython it
can be delayed arbitrarily long.
Using 'g.close()' on the other hand is always safe.
Fix guestfish (and other C tools) so that they ignore errors
when /etc/fstab contains bogus entries.
Update the documentation for inspect-get-mountpoints to emphasize
that callers must be aware of this when mounting the returned
values.
Add a regression test.
Update the example code ("inspect_vm") to reflect the way this
API ought to be called.
For more detail see:
https://bugzilla.redhat.com/show_bug.cgi?id=668574
