e_service_gesture: Delete cleanup_timer when the last touched finger is up

e_service_gesture: Delete cleanup_timer when the last touched finger is up

< Normal scenario >
1st finger touch down - add cleanup_timer
2nd finger touch down
1st finger touch up - delete cleanup_timer
2nd finger touch up - pressed_fingers is zero and _gesture_cleanup() is called

< Issue scenario >
1st finger touch down - add cleanup_timer
2nd finger touch down
1st finger touch up - delete cleanup_timer
2nd finger touch up - pressed_fingers is not zero (somehow) -> clean_timer
                      is not triggered -> pressed_fingers is NOT set to zero

< TO-BE >
1st finger touch down - add cleanup_timer
2nd finger touch down
1st finger touch up
2nd finger touch up - pressed_fingers is not zero (somehow) -> cleanup_timer
                      will be triggered -> pressed_fingers is set to zero

Change-Id: Id43ef2529adb735fa19d1ca24212f7bfb71d5060