Merge pull request #744 from PavelSindler/M860_fix

M860 fix: send busy messages

Firmware/Marlin_main.cpp

@@ -6315,8 +6315,6 @@ Sigma_Exit:
 		codenum = millis();
 		cancel_heatup = false;
 
-		KEEPALIVE_STATE(NOT_BUSY);
-
 		while ((!cancel_heatup) && current_temperature_pinda < setTargetPinda) {
 			if ((millis() - codenum) > 1000) //Print Temp Reading every 1 second while waiting.
 			{