Fix SemaTemplate/instantiate-field.cpp after r261297.
Fix SemaTemplate/instantiate-field.cpp after r261297.

For templates, fields can have incomplete types:

  template <class T>
  struct A2 {
    struct B;
    B b;
  };

Don't try to touch the DefinitionData of those fields.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@261301 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang