init.rc: Create /storage mountpoint so Dalvik can mark as slave in zygotes

Update for JellyB-CM-AOKP-10.1

Mount a tmpfs as /storage in order to create a mountpoint, so that Dalvik
can later mark /storage as slave in zygotes.  Must use tmpfs as rootfs
can't be bind mounted (otherwise "mount rootfs /storage /storage bind"
would work as an alternative).
CM10.1 Kernel INIT Defaults. from last update 25/01/13