Fix click on now in DateFilterControl (apache#4265)

When clicking on `now` or the infinity sign, the popover closes but the
value doesn't show in the label as expected.

superset/assets/javascripts/explore/components/controls/DateFilterControl.jsx

@@ -69,9 +69,8 @@ export default class DateFilterControl extends React.Component {
   setType(type) {
     this.setState({ type });
   }
-  setValue(val) {
-    this.setState({ type: 'free', free: val });
-    this.close();
+  setValueAndClose(val) {
+    this.setState({ type: 'free', free: val }, this.close);
   }
   setDatetime(dttm) {
     this.setState({ dttm: dttm.format().substring(0, 19) });
@@ -175,13 +174,15 @@ export default class DateFilterControl extends React.Component {
             >
               <Button
                 bsSize="small"
-                onClick={this.setValue.bind(this, 'now')}
+                className="now"
+                onClick={this.setValueAndClose.bind(this, 'now')}
               >
                 now
               </Button>
               <Button
                 bsSize="small"
-                onClick={this.setValue.bind(this, '')}
+                className="clear"
+                onClick={this.setValueAndClose.bind(this, '')}
               >
                 clear
               </Button>

superset/assets/spec/javascripts/explore/components/DateFilterControl_spec.jsx

@@ -42,6 +42,14 @@ describe('DateFilterControl', () => {
       expect(wrapper.state().num).to.equal('90');
     }, 10);
   });
+  it('sets now and closes', () => {
+    const label = wrapper.find('.now').first();
+    label.simulate('click');
+    setTimeout(() => {
+      expect(wrapper.state().free).to.equal('now');
+      expect(wrapper.find('.popover')).to.have.length(0);
+    }, 10);
+  });
   it('renders 2 dimmed sections', () => {
     const label = wrapper.find('.label').first();
     label.simulate('click');