Modified the way we report fields of records.

Modified the way we report fields of records.
Clang requires them to have complete types, but
we were previously only completing them if they
were of tag or Objective-C object types.

I have implemented a method on the ASTImporter
whose job is to complete a type.  It handles not
only the cases mentioned above, but also array
and atomic types.

<rdar://problem/13446777>

llvm-svn: 177672