Add -t msdos to mount line in script

mount -o loop,offset=$MYOFFSET,users,rw,umask=000 -t msdos $DEVICE /media/usbfd$FLOP || rmdir /media/usbfd$FLOP

my computer doesn't discovers the partion type by itself.
Merge pull request #1 from WouterRademaker/patch-1

Add -t msdos to mount line in script