Set is_set to True on restore_state
Set is_set to True on restore_state

In HPMC, restore_state correctly restored the shape state information, but left the is_set python variables as False -
thus preventing simulations from running correctly unless shape information was set from python. This commit fixes
the issue.

refs #289

joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue