SEPolicy to start hostapd via init

While here, remove a lot of extra permissions that we apparently
had because hostapd was inheriting fds from netd.

Bug: 30041118
Test: netd can request init to start/stop hostapd without denials.

Change-Id: Ia777497443a4226a201030eccb9dfc5a40f015dd
(cherry picked from commit 8a6c5f8553f6cc78237111daf22e59c572dde30c)
diff --git a/file_contexts b/file_contexts
index 7d55abe..9d5ee9f 100644
--- a/file_contexts
+++ b/file_contexts
@@ -283,7 +283,7 @@
 /data/misc/wifi(/.*)?           u:object_r:wifi_data_file:s0
 /data/misc/wifi/sockets(/.*)?   u:object_r:wpa_socket:s0
 /data/misc/wifi/sockets/wpa_ctrl.*   u:object_r:system_wpa_socket:s0
-/data/misc/wifi/hostapd(/.*)?   u:object_r:wpa_socket:s0
+/data/misc/wifi/hostapd(/.*)?   u:object_r:hostapd_socket:s0
 /data/misc/zoneinfo(/.*)?       u:object_r:zoneinfo_data_file:s0
 /data/misc/vold(/.*)?           u:object_r:vold_data_file:s0
 /data/misc/perfprofd(/.*)?      u:object_r:perfprofd_data_file:s0