[Tizen] Re-enable pinch zoom in Tizen 2.X.

Tizen 2.X does not support XInput2.2 touch event.

Chromium had hack to emulate multi touch using XIButton events. However,
unfortunately, following commit dropped the hack, because Chromium officially
supports XInput 2.2 or above.

So this PR reverts the commit to support multi touch to Tizen 2.X. If you bump
up to Tizen 3.0, this commit can be removed.

Revert "x11: Fix a few touch-event related issues:"

This reverts commit f8a9520395d7a1e478e6f134d1bb016f45087d00.

BUG=https://crosswalk-project.org/jira/browse/XWALK-445