SCUMM: Fix glitch introduced by DOTT Chron-O-John workaround

The mainRoutine() function returns a byte, not a bool. This caused text
to be partly erased when drugging the piranha poodles in MI1. Probably
other things as well.

engines/scumm/costume.cpp

@@ -948,7 +948,7 @@ byte ClassicCostumeRenderer::drawLimb(const Actor *a, int limb) {
 				}
 			}
 
-			bool result = mainRoutine(xmoveCur, ymoveCur);
+			byte result = mainRoutine(xmoveCur, ymoveCur);
 
 			_mirror = mirror;
 			return result;