Fixed some problems with type deportation:

  - made sure we tell Clang not to try to
    complete the type since it can't be
    completed from its origin any more; and

  - fixed a silly bug where we tried to
    forget about the original decl's origins
    rather than the deported decl's origin.

These produced some crashes in ptr_refs,
especially under libgmalloc.

<rdar://problem/13256150>