Reset mounts?

[Wesley Shields]

Earlier this week I was using tc to set mounts for various jails and
ports trees.  I then tried to remove those mounts using tc and was
unable to do so.  I came up with the following patch which adds a -r
argument to setSrcMount and setPortsMount which will reset the mount.

Is doing this a good idea, or was there some other way?  Trying 'tc
setPortsMount -p FreeBSD-Ports -m ""' didn't work.

This is my first time really looking at the underlying code so please be
nice.  :)

-- WXS