The unix_socket operations for testing getopt and setopt permissions
were occurring back to back. This patch breaks them up into "pre-bind"
and "post-bind" operations. The setopt operation now occurs pre-bind
while the getopt operation happens post-bind. This allows for the test
policy to test setopt without an addr= conditional and to test getopt
with an addr= conditional.

Additionally, the wrapper functions that call setsockopt()/getsockopt()
are moved into a new file that both unix_socket.c and
unix_socket_client.c can reuse.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Steve Beattie <steve@nxnw.org>