BGE: Fixing memory leaks when deactivating Sensors, Controllers, or actuators.

Found by Coverity and confirmed with Valgrind.

source/gameengine/Converter/KX_ConvertActuators.cpp

@@ -1122,6 +1122,8 @@ void BL_ConvertActuators(const char* maggiename,
 			// done with baseact, release it
 			baseact->Release();
 		}
+		else if (baseact)
+			baseact->Release();
 		
 		bact = bact->next;
 	}

source/gameengine/Converter/KX_ConvertControllers.cpp

@@ -240,6 +240,8 @@ void BL_ConvertControllers(
 			//done with gamecontroller
 			gamecontroller->Release();
 		}
+		else if (gamecontroller)
+			gamecontroller->Release();
 		
 		bcontr = bcontr->next;
 	}

source/gameengine/Converter/KX_ConvertSensors.cpp

@@ -640,6 +640,9 @@ void BL_ConvertSensors(struct Object* blenderobject,
 			gamesensor->Release();
 			
 		}
+		else if (gamesensor)
+			gamesensor->Release();
+
 		sens=sens->next;
 	}
 }