Avoid race condition that gets PanService stuck in STATE_DISCONNECTED.

http://b/12788418

Change-Id: I7cc43db047457eb6a4ac501770a714eef0ed6422
Update PAN JNI code to match updated interface definition.

This also fixes some weird internal reordering of arguments. All
of the implementations should match the interfaces now.

http://b/12853951

Change-Id: I019da4892204dd92ebf203e77bdb23af96c57697