Fix bug #512676 - Enable create/bind on SELinux netlink socket for run_init

The run_init code calls avc_* functions, but the following failure
occurs:

~# run_init rc-service nfs status
Authenticating swift.
run_init: avc.c:74: avc_context_to_sid_raw: Assertion `avc_running' failed.
Segmentation fault

AVC denials are shown related to the netlink_selinux_socket class
(create/bind privileges) and signal (possibly to handle failure).

Allowing them has the run_init code run properly again.