Segfault fix - the eef name must first be converted to its parent's link's model

... in order to correctly find attached bodies

I'm not sure if this is the perfect fix, but currently with Baxter it segfaults and this fix works. Seems like this part of the code is pretty messy, despite the recent commits.

In pick actions, what is the official location to attach an object? Somehow it is attached objects to the end effector's parent link for Baxter.