recovery: Don't automount external storage at startup
recovery: Don't automount external storage at startup

 * Do it for hotplug and on-demand only.

Change-Id: I9c0ca96203a8ff1f16fa42e31f426cd25bdaba1d

InsomniaAOSP/platform_bootable_recovery,randomblame/bootable_recovery,Plain-Andy/android_platform_bootable_recovery,randomblame/bootable_recovery,DerTeufel/dualboot_recovery,Plain-Andy/android_platform_bootable_recovery,DerTeufel/dualboot_recovery,InsomniaAOSP/platform_bootable_recovery,76Demented/bootable_recovery-,randomblame/bootable_recovery,Plain-Andy/android_platform_bootable_recovery,InsomniaAOSP/platform_bootable_recovery,76Demented/bootable_recovery-,DerTeufel/dualboot_recovery,kylinmoddev/android_bootable_recovery,Plain-Andy/android_platform_bootable_recovery,kylinmoddev/android_bootable_recovery,DerTeufel/dualboot_recovery,InsomniaAOSP/platform_bootable_recovery,InsomniaAOSP/platform_bootable_recovery,76Demented/bootable_recovery-,DerTeufel/dualboot_recovery,randomblame/bootable_recovery,kylinmoddev/android_bootable_recovery,76Demented/bootable_recovery-,randomblame/bootable_recovery,kylinmoddev/android_bootable_recovery,76Demented/bootable_recovery-