Make sure that mount_msdosfs is available and make msdos3 a bit more
verbose.

Sponsored by:	EMC / Isilon storage division
Make sure that mount_msdosfs is installed.

Sponsored by:	EMC / Isilon storage division
Added check for mount_msdosfs installed.

Sponsored by:	EMC / Isilon storage division
Stop test at first error, make error message more informative, cleanup code
and print FAIL on error.

Sponsored by:	EMC / Isilon storage division