Pre-expands the role and user caches used in context validation when
conerting a cildb to a binary policydb. This is currently only done
when loading a binary policy and prevents context validation from
working correctly with a newly built policy (i.e., when semanage builds
a new policy and then runs genhomedircon).
Also adds declarations for the hashtable mapping functions used:
policydb_role_cache and policydb_user_cache().
Signed-off-by: Gary Tierney <gary.tierney@gmx.com>