Correcting some issues with the Time-Series Table (apache#8746)

* default timeLag to 0

* correct placeholder

* remove random link default

superset/assets/src/explore/components/controls/TimeSeriesColumnControl.jsx

@@ -89,7 +89,7 @@ export default class TimeSeriesColumnControl extends React.Component {
       colType: this.props.colType,
       width: this.props.width,
       height: this.props.height,
-      timeLag: this.props.timeLag,
+      timeLag: this.props.timeLag || 0,
       timeRatio: this.props.timeRatio,
       comparisonType: this.props.comparisonType,
       showYAxis: this.props.showYAxis,
@@ -223,7 +223,7 @@ export default class TimeSeriesColumnControl extends React.Component {
                 value={this.state.timeRatio}
                 onChange={this.onTextInputChange.bind(this, 'timeRatio')}
                 bsSize="small"
-                placeholder="Time Lag"
+                placeholder="Time Ratio"
               />,
             )}
           {this.state.colType === 'time' &&

superset/assets/src/explore/controls.jsx

@@ -1263,7 +1263,7 @@ export const controls = {
       'The URL, this control is templated, so you can integrate ' +
         '{{ width }} and/or {{ height }} in your URL string.',
     ),
-    default: 'https://www.youtube.com/embed/AdSZJzb-aX8',
+    default: '',
   },
 
   x_axis_label: {

superset/assets/src/visualizations/TimeTable/TimeTable.jsx

@@ -168,7 +168,7 @@ class TimeTable extends React.PureComponent {
     let errorMsg;
     if (column.colType === 'time') {
       // Time lag ratio
-      const { timeLag } = column;
+      const timeLag = column.timeLag || 0;
       const totalLag = Object.keys(reversedEntries).length;
       if (timeLag >= totalLag) {
         errorMsg = `The time lag set at ${timeLag} is too large for the length of data at ${reversedEntries.length}. No data available.`;