Allow system_server to read /data/misc/sensors, /data/system/sensors.

Addresses denials such as:
avc: denied { search } for comm="Binder_7" name="sensors" dev="mmcblk0p30" ino=188436 scontext=u:r:system_server:s0 tcontext=u:object_r:sensors_data_file:s0 tclass=dir

Change-Id: I27f95642337c52007379c392195295d992e0afa8
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
diff --git a/sepolicy/system_server.te b/sepolicy/system_server.te
index 356afb1..f415362 100644
--- a/sepolicy/system_server.te
+++ b/sepolicy/system_server.te
@@ -13,3 +13,7 @@
 unix_socket_send(system_server, mpdecision, mpdecision)
 allow system_server mpdecision:unix_stream_socket sendto;
 allow system_server mpdecision_socket:dir search;
+
+# Read /data/misc/sensors or /data/system/sensors.
+allow system_server sensors_data_file:dir r_dir_perms;
+allow system_server sensors_data_file:file r_file_perms;