Make *-apex-info-list.xml readable by shell

Enables CTS testing of the bootstrap apexes.

Bug: 186767843
Test: adb shell cat bootstrap-apex-info-list.xml works without root
Change-Id: Icf56d32d296f5a42160dbd9ea90a89c8b4db6aa7
diff --git a/private/shell.te b/private/shell.te
index 0e94cd1..f61c874 100644
--- a/private/shell.te
+++ b/private/shell.te
@@ -102,6 +102,9 @@
 allow shell self:perf_event { open read write kernel };
 neverallow shell self:perf_event ~{ open read write kernel };
 
+# Allow shell to read /apex/apex-info-list.xml
+allow shell apex_info_file:file r_file_perms;
+
 # Set properties.
 set_prop(shell, shell_prop)
 set_prop(shell, ctl_bugreport_prop)