Merge tag 'android-6.0.0_r26' into HEAD

Android 6.0.0 release 26
* tag 'android-6.0.0_r26':
  emulator-fingerprint: Exit listener thread on HAL close
  init.ranchu.rc: Add dhcpcd_eth0 service
  Support removing a fingerprint
  Removes overriding value of EXTERNAL_STORAGE for arm64.
  Add some guidance documentation to the emulator

Change-Id: Ie48fadf4fb5774601e9a09e2f7c8df95cd262cc1