selinux: Allow ovs-ctl force-reload-kmod.

selinux: Allow ovs-ctl force-reload-kmod.

When invoking ovs-ctl force-reload-kmod via '/etc/init.d/openvswitch
force-reload-kmod', spurious errors would output related to 'hostname'
and 'ip', and the system's selinux audit log would complain about some
of the invocations such as those listed at the end of this commit message.

This patch loosens restrictions for openvswitch_t (used for ovs-ctl, as
well as all of the OVS daemons) to allow it to execute 'hostname' and
'ip' commands, and also to execute temporary files created as
openvswitch_tmp_t. This allows force-reload-kmod to run correctly.

Example audit logs:
type=AVC msg=audit(1468515192.912:16720): avc:  denied  { getattr } for
pid=11687 comm="ovs-ctl" path="/usr/bin/hostname" dev="dm-1"
ino=33557805 scontext=system_u:system_r:openvswitch_t:s0
tcontext=system_u:object_r:hostname_exec_t:s0 tclass=file

type=AVC msg=audit(1468519445.766:16829): avc:  denied  { getattr } for
pid=13920 comm="ovs-save" path="/usr/sbin/ip" dev="dm-1" ino=67572988
scontext=unconfined_u:system_r:openvswitch_t:s0
tcontext=system_u:object_r:ifconfig_exec_t:s0 tclass=file

type=AVC msg=audit(1468519445.890:16833): avc:  denied  { execute } for
pid=13849 comm="ovs-ctl" name="tmp.jdEGHntG3Z" dev="dm-1" ino=106876762
scontext=unconfined_u:system_r:openvswitch_t:s0
tcontext=unconfined_u:object_r:openvswitch_tmp_t:s0 tclass=file

VMware-BZ: #1692972
Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Flavio Leitner <fbl@sysclose.org>