does not scrollback to first tab

[jtadiarca]

I have 4 tabs in my activity and here's the scenario:

1. From the first tab, scroll all the way to the last/4th tab.
2. Click the first tab indicator.

Expectes results:

• Scrolls back to first tab Actual results: -Nothing happens. Does not scroll back to first tab -This only happens to the first tab. Other tabs(2nd & 3rd) work fine.

[yanzm]

https://github.com/yanzm/MaterialTabHost/pull/1