Remove -unconfineddomain from neverallow rules.

With the sepolicy-analyze neverallow checking, attribute
expansion is performed against the device policy and therefore
we do not want our neverallow rules to exempt domains from
consideration based on an attribute (e.g. -unconfineddomain).
Otherwise, device policy could pass the neverallow check just
by adding more domains to unconfineddomain.  We could of course
add a CTS test to check the list of unconfineddomains against
a whitelist, but it seems desirable regardless to narrow these
neverallow rules to only the specific domains required.

There are three such neverallow rules in current policy: one
on creating unlabeled files, one on accessing /dev/hw_random, and
one on accessing a character device without a specific type.  The
only domain in unconfineddomain that appears to have a legitimate
need for any of these permissions is the init domain.  Replace
-unconfineddomain with -init in these neverallow rules, exclude these
permissions from unconfineddomain, and add these permissions to init if
not already explicitly allowed.  auditallow accesses by init to files
and character devices left in the generic device type so we can monitor
what is being left there, although it is not necessarily a problem unless
the file or device should be accessible to others.

Change-Id: If6ee1b1a337c834971c6eb21dada5810608babcf
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>