Fix cmake build.

Add CONFIG_UNPOISON_PARTITION_CTX to cmake configuration. Also, remove
deleted file from CMakeLists.txt.

BUG=https://bugs.chromium.org/p/aomedia/issues/detail?id=76

Change-Id: Ic26c19c0a12d638eebe94fd1eecda4a3e6c85bfc
3 files changed