android_chooser workflow

 * android_chooser works as follow:
 *
 * 1) read configuration from kernel commandline
 * 2) extract android initrd over NEWROOT
 * 3) run android udev chrooted into NEWROOT
 * 4) read fstab file
 * 5) find what android blockdevices handle our mountpoints
 * 6) associate fs files to loop devices
 * 7) wait that android blockdevices has been found by udev
 * 8) replace the android blockdevices with symlinks to loop devices
 * 9) chroot into NEWROOT and start the android init process
 *