Fix crash when rotating video fragment

Due to a recent framework change,
https://googleplex-android-review.git.corp.google.com/#/c/659363/

TextureView will now crash if setSurfaceTexture is called before
the TextureView is attached to the window. Use an
OnAttachStateListener to call setSurfaceTexture only after the view
is attached to the window.

Change-Id: Ic61302fb81461a00ae9e61352a1798d6c8b61318