initramfs: cleanup incomplete rootfs

initramfs: cleanup incomplete rootfs

Unpacking an external initrd may fail e.g.  not enough memory.  This
leads to an incomplete rootfs because some files might be extracted
already.  Fixed by cleaning the rootfs so the kernel is not using an
incomplete rootfs.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Engraf <[email protected]>
Cc: Dominik Brodowski <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Philippe Ombredanne <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>