[PCH] Fix serialization of an ImportDecl.

ImportDecl's module ID was not written out and the reader accepted as module ID
the serialized:
  Record.push_back(!IdentifierLocs.empty());

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@165087 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed