Fix a crash in TrustedOverlayHost

Speculative fix for NPE crashes. If the surface package is released,
the surface control will be null. This can happen if the surface
package is released by the caller before the overlay is removed.

Change-Id: I7eb50abd2b8ca21053d9448f61b1097b43a6609c
Flag: EXEMPT bug fix
Test: Presubmit
Fixes: 339761833