[automerger skipped] minadbd: Support `adb reboot` under sideload/rescue modes.
am: 7b9b7db877 -s ours
am skip reason: change_id I84daf63e3360b7b4a0af5e055149a4f54e10ba90 with SHA1 10f441a9db is in history

Change-Id: I77fba90b8a5506ff4754bee0b6dd569efe015685