r.mountsLockfile.Touch() directly in saveMounts()
r.mountsLockfile.Touch() directly in saveMounts()

... instead of doing it in callers.

This makes it clearer that the Touch() always happens,
and it adds error handling.

OTOH there might be some undocumented reason why the Touch()
should happen in callers even if the saveMounts() call is
not reached.

Signed-off-by: Miloslav Trmač <9c008e38982a5397deb855345fb164f0558459ae@redhat.com>

containers/storage,containers/storage,containers/storage