The function only uses the passed command as a const buffer and makes a
copy immediately. As such, there is also no need for a destroy callback
as the caller can simply clean up afterwards.
Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net>
If the button shield command cannot be executed due to an underlying
error then resp is NULL. Avoid the crash by adding the appropriate
check.
Closes: #694
Benjamin Berg