If the bolt head sheared off flush with the bolt and there is no protruding threads from the bolt head. By removing your shock from the mount there might be a protruding stub left.
Try to grab it with vice grips and see if it easily turns out. If it does not easily turn out try to thread a nut on it and have someone with a mig centre weld the nut to the bolt is one solution. Just make sure whoever does it has done this a lot of times. Works very well usually and the heat from the nut weld travelling down the actual threaded part seems to help the removal situation as well to some extent.
If the break is too low for this then the easy out is your best bet. What you have going for you is the bolt thread is not rusted in place as you just inserted it.