[IMPROVED] Inside- and outside-parent jail/chroot mounting/unmounting operations...

[IMPROVED] Inside- and outside-parent jail/chroot mounting/unmounting operations by portsreinstall-chroot(8) and portsreinstall-chroot-mount(8) are now safely protected each other.

 Changes to be committed:
	modified:   bin/portsreinstall-chroot
	modified:   lib/chroot-mount/libcommand.sh
	modified:   lib/chroot/libcommand.sh
	modified:   lib/chroot/libcommand_do.sh
	modified:   lib/chroot/libdatabase_maintain.sh
	modified:   lib/chroot/libfs.sh
	modified:   lib/chroot/libmain.sh
	modified:   lib/libfs.sh
	modified:   lib/libmain.sh
	modified:   man/portsreinstall.8
	modified:   share/bin/portsreinstall-chroot-mount