[ODRHash] Finish FieldDecl support by handling mutable and initializers.

https://reviews.llvm.org/rL296170

llvm-svn: 296198
diff --git a/clang/lib/AST/ODRHash.cpp b/clang/lib/AST/ODRHash.cpp
index 208d5f3..28b2eff 100644
--- a/clang/lib/AST/ODRHash.cpp
+++ b/clang/lib/AST/ODRHash.cpp
@@ -190,6 +190,9 @@
     if (IsBitfield) {
       AddStmt(D->getBitWidth());
     }
+
+    Hash.AddBoolean(D->isMutable());
+    AddStmt(D->getInClassInitializer());
   }
 };