MFH: r433857

The late mount option is required for systems with a seperate boot partition
(e.g. systems with an encrypted root partition) where it is impossible for the
fdescfs module to be autoloaded when /boot/kernel isn't available yet. Change
pkg-message accordingly.

Also change 'fdesc' mount point name to 'fdescfs' to simplify things: this way
'mount fdescfs' will work just as fine as 'umount fdescfs'. The less things to
remember - the better it is.

PR: 216985
Submitted by: John Smith <godevilove@ya.ru>
Approved by: ports-secteam (blanket)