Use RECOVERY_PRE_COMMAND before calling __reboot() recovery

For the Power menu,
frameworks/base/core/jni/android_os_Power.cpp#L180
already uses RECOVERY_PRE_COMMAND if
TARGET_RECOVERY_PRE_COMMAND is defined in the
BoardConfig.mk for a device to make a system() call before
calling __reboot() for recovery. This commit adds
the same thing to the other places that we know we are
getting into recovery using __reboot(), namely,
adb reboot recovery, the reboot binary and init
in the case of errors.

Signed-off-by: Humberto Borba <humberos@gmail.com>

Conflicts:
	libcutils/Android.mk
	libcutils/android_reboot.c

Change-Id: Id0fb6675accd732f46d4b10e0fce459d2582875c

libcutils : reboot mount fix

On aries for eg, cache needs to be rw for the RECOVERY_PRE_COMMAND to
work because we write to /cache/.startrecovery

This patchset moves the RECOVERY_PRE_COMMAND prior to the remount.

Conflicts:
	libcutils/android_reboot.c

Change-Id: I4bd97517e00cdd117191d29b610e9623ad7d9255

RECOVERY_PRE_COMMAND_CLEAR_REASON and extended reboot arguments

fix the 2 new warnings created by our 4-lines recovery patch ;p

Allow also to override toolbox reboot applet, for bootmenu

Conflicts:
	libcutils/Android.mk
	libcutils/android_reboot.c
	toolbox/Android.mk

Change-Id: I2bff30b5f911e7b9ba8f26593523368223b12814

android_reboot: execute recovery pre command while rw mounted

The TARGET_RECOVERY_PRE_COMMAND might need to write to mounted
partitions, so execute it before re-mounting everything as read-
only.

Change-Id: I66b2e81b8c05b9aa6eeddbfb589619ce53e36e2b