Default to socket_device for anything under /dev/socket.

Otherwise sockets that have no specific entry match the /dev(/.*) entry
instead, leaving them in device type rather than socket_device type.
Every socket should get its own entry regardless, but this at least puts
it into a more specific type by default.

Change-Id: I97f7999af7f9f83484d3a51440dda791d3726f1a
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

file_contexts

@@ -75,7 +75,7 @@
 /dev/rpmsg-omx[0-9]	u:object_r:rpmsg_device:s0
 /dev/rproc_user	u:object_r:rpmsg_device:s0
 /dev/snd(/.*)?		u:object_r:audio_device:s0
-/dev/socket		u:object_r:socket_device:s0
+/dev/socket(/.*)?	u:object_r:socket_device:s0
 /dev/socket/adbd	u:object_r:adbd_socket:s0
 /dev/socket/bluetooth	u:object_r:bluetooth_socket:s0
 /dev/socket/dnsproxyd	u:object_r:dnsproxyd_socket:s0