Allow system settings to read /proc/version

Used to display kernel version in settings app.

avc: denied { read } for name="version" dev="proc"
scontext=u:r:system_app:s0 tcontext=u:object_r:proc_version:s0
tclass=file permissive=0

Bug: 66985744
Test: kernel version now displayed in settings app.
Change-Id: I53f92f63362b900347fd393a40d70ccf5d220d30
diff --git a/private/system_app.te b/private/system_app.te
index 9d2ee28..904b851 100644
--- a/private/system_app.te
+++ b/private/system_app.te
@@ -92,7 +92,10 @@
 r_dir_file(system_app, sysfs_type)
 
 # settings app reads /proc/version and /proc/pagetypeinfo
-allow system_app proc:file r_file_perms;
+allow system_app {
+  proc
+  proc_version
+}:file r_file_perms;
 
 control_logd(system_app)
 read_runtime_log_tags(system_app)