CXXConditionDeclExpr expression node is an lvalue.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@56093 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 9452db4..ca92c81 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -460,6 +460,8 @@
             ? LV_InvalidExpression : LV_Valid);
   case CXXDefaultArgExprClass:
     return cast<CXXDefaultArgExpr>(this)->getExpr()->isLvalue(Ctx);
+  case CXXConditionDeclExprClass:
+    return LV_Valid;
   default:
     break;
   }