coverity#1437410 Dereference after null check

Change-Id: Icf67be4419d1eeb5ef92d709d6453e6651b15723
Reviewed-on: https://gerrit.libreoffice.org/56119Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/docnode/ndtbl1.cxx

@@ -89,9 +89,11 @@ SwTableFormatCmp::SwTableFormatCmp( SwFrameFormat *pO, SwFrameFormat *pN, sal_In
 SwTableFormatCmp::~SwTableFormatCmp()
 {
     if (pOld)
+    {
         pOld->Remove(this);
-    if (!pOld->HasWriterListeners())
-        delete pOld;
+        if (!pOld->HasWriterListeners())
+            delete pOld;
+    }
 }
 
 // static