Allow init to restorecon sysfs files.

The boot-time restorecon_recursive("/sys") occurs while still in
the kernel domain, but init.rc files may nonetheless perform
restorecon_recursive of parts of /sys created later and therefore
require this permission.   Required for:
https://android-review.googlesource.com/#/c/101800/



Change-Id: I68dc2c6019a1f9deae3eec5c2f068365ce2372e5
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>