Copter: Remove rangefinder distance prearm check

ArduCopter/AP_Arming.cpp

@@ -172,14 +172,6 @@ bool AP_Arming_Copter::parameter_checks(bool display_failure)
         }
 #endif
 
-        #if RANGEFINDER_ENABLED == ENABLED && OPTFLOW == ENABLED
-        // check range finder if optflow enabled
-        if (copter.optflow.enabled() && !copter.rangefinder.pre_arm_check()) {
-            check_failed(ARMING_CHECK_PARAMETERS, display_failure, "check range finder");
-            return false;
-        }
-        #endif
-
         #if FRAME_CONFIG == HELI_FRAME
         // check helicopter parameters
         if (!copter.motors->parameter_check(display_failure)) {