Update libpowermanager to expose enum and export headers.

Move libpowermanager's transaction ID enum (needed when
implementing BnPowerManager::onTransact()) into
IPowerManager.h and update the library's Android.mk file to
export its headers.

Bug: 22122485
Change-Id: Ie97198c3d2ebe8e880125e19a001ef7162009858
3 files changed