msxml: Allow insertBefore to have a NULL output parameter.

dlls/msxml3/node.c

@@ -373,7 +373,7 @@ static HRESULT WINAPI xmlnode_insertBefore(
 
     TRACE("(%p)->(%p,var,%p)\n",This,newChild,outNewChild);
 
-    if (!(newChild && outNewChild))
+    if (!newChild)
         return E_INVALIDARG;
 
     switch(V_VT(&refChild))
@@ -414,7 +414,9 @@ static HRESULT WINAPI xmlnode_insertBefore(
 
     IXMLDOMNode_Release(new);
     IXMLDOMNode_AddRef(newChild);
-    *outNewChild = newChild;
+    if(outNewChild)
+        *outNewChild = newChild;
+
     TRACE("ret S_OK\n");
     return S_OK;
 }