Use forward declarations for ASTDeclContextNameLookupTable and add a missing delete.

It would be nice to use OwningPtr here, but DeclContextInfo is stored in a DenseMap.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154763 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/Module.cpp b/lib/Serialization/Module.cpp
index 16b95e2..ff241d3 100644
--- a/lib/Serialization/Module.cpp
+++ b/lib/Serialization/Module.cpp
@@ -45,8 +45,7 @@
        E = DeclContextInfos.end();
        I != E; ++I) {
     if (I->second.NameLookupTableData)
-      delete static_cast<ASTDeclContextNameLookupTable*>(
-                                                 I->second.NameLookupTableData);
+      delete I->second.NameLookupTableData;
   }
   
   delete static_cast<ASTIdentifierLookupTable *>(IdentifierLookupTable);