L2E: properly init two pass rc parameters

L2E: properly init two pass rc parameters

Two pass rc parameters are only initialized in the second pass
in vp9 normal two pass encoding.
However, the simple_encode API queries the keyframe group, arf group,
and number of coding frames without going throught the two pass
route.
Since recent libvpx rc changes, parameters in the TWO_PASS
struct have a great influence on the determination of the above
information.
We therefore need to properly init two pass rc parameters in
the simple_encode related environment.

Change-Id: Ie14b86d6e7ebf171b638d2da24a7fdcf5a15c3d9