coverity#1438214 Unchecked dynamic_cast

Change-Id: I68e1569835a1e981f57aabf2565f3eb2c619d296
Reviewed-on: https://gerrit.libreoffice.org/58608
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/unocore/unotbl.cxx

@@ -2280,10 +2280,10 @@ uno::Reference<table::XCellRange> GetRangeByName(
     pUnoCursor->SetMark();
     pUnoCursor->GetPoint()->nNode = *pBRBox->GetSttNd();
     pUnoCursor->Move( fnMoveForward, GoInNode );
-    SwUnoTableCursor* pCursor = dynamic_cast<SwUnoTableCursor*>(pUnoCursor.get());
+    SwUnoTableCursor& rCursor = dynamic_cast<SwUnoTableCursor&>(*pUnoCursor.get());
     // HACK: remove pending actions for selecting old style tables
-    UnoActionRemoveContext aRemoveContext(*pCursor);
-    pCursor->MakeBoxSels();
+    UnoActionRemoveContext aRemoveContext(rCursor);
+    rCursor.MakeBoxSels();
     // pUnoCursor will be provided and will not be deleted
     return SwXCellRange::CreateXCellRange(pUnoCursor, *pFormat, rDesc).get();
 }