Fix: JS error when there are no fill options available

Fix: Vertical fill not available when it was the only fill type available (other's having been deleted) and a single column was used

- https://datatables.net/forums/discussion/58669

js/dataTables.autoFill.js

@@ -294,7 +294,7 @@ $.extend( AutoFill.prototype, {
 			var result = actions[ available[0] ].execute( dt, cells );
 			this._update( result, cells );
 		}
-		else {
+		else if ( available.length > 1 ) {
 			// Multiple actions available - ask the end user what they want to do
 			var list = this.dom.list.children('ul').empty();
 
@@ -1061,7 +1061,7 @@ AutoFill.actions = {
 
 	fillVertical: {
 		available: function ( dt, cells ) {
-			return cells.length > 1 && cells[0].length > 1;
+			return cells.length > 1;
 		},
 
 		option: function ( dt, cells ) {