As has been said, RAW the answer is no. I probably would not allow this, as one important limitation of the battlemaster is that he can't know all the maneuvers. He has to pick and choose. Since Pushing Attack (if successful) would break a grapple, allowing Disarming Strike to do so gives that maneuver extra effectiveness over the others. Also, since the ogre does not drop his weapon when grappling, the Disarming Strike still affects the ogre. It just wouldn't break the grapple.