coverity#735883 Unchecked dynamic_cast

Change-Id: I4dec526d78dfaa1d894ab1be205e58e1224fbf72

svx/source/table/tablemodel.cxx

@@ -1124,12 +1124,12 @@ void TableModel::merge( sal_Int32 nCol, sal_Int32 nRow, sal_Int32 nColSpan, sal_
 
     // merge first cell
     CellRef xOriginCell( dynamic_cast< Cell* >( getCellByPosition( nCol, nRow ).get() ) );
-    if( xOriginCell.is() )
-    {
+    if(!xOriginCell.is())
+        return;
+
     if( bUndo )
         xOriginCell->AddUndo();
     xOriginCell->merge( nColSpan, nRowSpan );
-    }
 
     sal_Int32 nTempCol = nCol + 1;
 
@@ -1151,9 +1151,6 @@ void TableModel::merge( sal_Int32 nCol, sal_Int32 nRow, sal_Int32 nColSpan, sal_
     }
 }
 
-
-
-
 void TableModel::updateRows()
 {
     sal_Int32 nRow = 0;
@@ -1164,8 +1161,6 @@ void TableModel::updateRows()
     }
 }
 
-
-
 void TableModel::updateColumns()
 {
     sal_Int32 nColumn = 0;
@@ -1176,8 +1171,6 @@ void TableModel::updateColumns()
     }
 }
 
-
-
 } }
 
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