selinux: Fix ceph-iscsi configfs access

selinux: Fix ceph-iscsi configfs access

This fixes the the following selinux error when using ceph-iscsi's
rbd-target-api daemon (rbd-target-gw has the same issue). They are
a result of the a python library, rtslib, which the daemons use.

Additional Information:
Source Context                system_u:system_r:ceph_t:s0
Target Context                system_u:object_r:configfs_t:s0
Target Objects
/sys/kernel/config/target/iscsi/iqn.2003-01.com.re
                              dhat:ceph-iscsi/tpgt_1/attrib/authentication
[
                              file ]
Source                        rbd-target-api
Source Path                   /usr/libexec/platform-python3.6
Port                          <Unknown>
Host                          ans8
Source RPM Packages           platform-python-3.6.8-15.1.el8.x86_64
Target RPM Packages
Policy RPM                    selinux-policy-3.14.3-20.el8.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     ans8
Platform                      Linux ans8 4.18.0-147.el8.x86_64 #1 SMP
Thu Sep 26
                              15:52:44 UTC 2019 x86_64 x86_64
Alert Count                   1
First Seen                    2020-01-08 18:39:47 EST
Last Seen                     2020-01-08 18:39:47 EST
Local ID                      6f8c3415-7a50-4dc8-b3d2-2621e1d00ca3

Raw Audit Messages
type=AVC msg=audit(1578526787.577:68): avc:  denied  { ioctl } for
pid=995 comm="rbd-target-api"
path="/sys/kernel/config/target/iscsi/iqn.2003-01.com.redhat:ceph-iscsi/tpgt_1/attrib/authentication"
dev="configfs" ino=25703 ioctlcmd=0x5401
scontext=system_u:system_r:ceph_t:s0
tcontext=system_u:object_r:configfs_t:s0 tclass=file permissive=1

type=SYSCALL msg=audit(1578526787.577:68): arch=x86_64 syscall=ioctl
success=no exit=ENOTTY a0=34 a1=5401 a2=7ffd4f8f1f60 a3=3052cd2d95839b96
items=0 ppid=1 pid=995 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0
egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm=rbd-target-api
exe=/usr/libexec/platform-python3.6 subj=system_u:system_r:ceph_t:s0
key=(null)

Hash: rbd-target-api,ceph_t,configfs_t,file,ioctl

Signed-off-by: Mike Christie <mchristi@redhat.com>