kmod_modprobe: properly handle install/remove commands

kmod_modprobe: properly handle install/remove commands

Handle install/remove commands just like modprobe does. Test configure
file:

install installme echo "this is a install message"
remove  removeme echo "this is a remove message"

Tests:

$ ./tools/kmod-modprobe installme
this is a install message

$ ./tools/kmod-modprobe -r removeme
this is a remove message

$ ./tools/kmod-modprobe removeme
FATAL: Module removeme not found.

./tools/kmod-modprobe -r installme
FATAL: Module installme not found.