supporting RBACSEP in genhomedircon

New version of the previous genhomedircon-rbacsep patch with some changes. A bit of a delay as I had to get in a libsepol/cil fix which was blocking this.

1. Remove semanage.conf option
2. Drop unrelated change
3. Adds a new homedir_role member to the genhomedircon_user struct.
4. Sets homedir_role if the SELinux users prefix is a valid role for that user.
5. Replaces all roles with homedir_role in context specifications if homedir_role is set.

One issue that came up when writing these patches is that genhomedircon squashes logging [1] for some reason, which can result in no warning / info messages and an empty file_contexts.homedirs file if policy has been incorrectly configured. Can we get rid of this behavior or add a flag to conditionally enable logging?

Dominick Grift helpfully created some test images that demo DSSP policy working with both RBACSEP and non-RBACEP:
https://tfirg.asu.su/2016/10/03/garys-patches/

There are still some rough edges though, for example in policy you can't write a statement like: (userprefix id role) and put it in an abstract namespace, since it is interpreted as a literal:

(block usersubj
(blockabstract usersubj)
(user id)
(role role)
(userrole id role)
(userprefix id role))

(block wheel
(blockinherit usersubj))

Which leaves us with a (userid, prefix) tuple of (wheel.id, role) [wheel.id might even just be id here, haven't checked if users are expanded or also taken as literals].

Though this is something I can look at later if all is well here.

[1] https://github.com/SELinuxProject/selinux/blob/master/libsemanage/src/genhomedircon.c#L568-L572

Gary Tierney (1):
genhomedircon: use userprefix as the role for homedir content

 libsemanage/src/genhomedircon.c | 38 +++++++++++++++++++++++++++++++++++---
 1 file changed, 35 insertions(+), 3 deletions(-)

2.4.11