tools: ratbagctl.devel: fix exception if the given arguments are wrong
tools: ratbagctl.devel: fix exception if the given arguments are wrong

"sudo ./build/ratbagctl.devel profile 2 4" returns an exception with cmd
being unknown.

Signed-off-by: Benjamin Tissoires <7a0e50e3f6a0939db82b6a8a423c08a163896f41@gmail.com>

libratbag/libratbag,libratbag/libratbag,whot/libratbag,whot/libratbag,libratbag/libratbag,whot/libratbag