bootcontrol: Reduce the number of writes in the set active slot function

We now write the 'gpt_disk' structure back to storage only once per each
physical disk.

Also did a minor cleanup of the code.

Bug: 28352938
Bug: 29436641
Change-Id: Id4fd887fe2978f9cd17447e9a1b715f0a8df5073
2 files changed
tree: 8a830a985bec3d2ecdb0dad6ccd7ed1fa13d34d9
  1. Android.mk
  2. boot_control.cpp
  3. NOTICE