runas: grant access to seapp_contexts files

To be replaced by commit 1e149967
seapp_context: explicitly label all seapp context files

Test: build policy
Change-Id: I8d30bd1d50b9e4a55f878c25d134907d4458cf59
Merged-In: I0f0e937e56721d458e250d48ce62f80e3694900f

public/runas.te

@@ -25,6 +25,10 @@ selinux_check_context(runas) # validate context
 allow runas self:process setcurrent;
 allow runas non_system_app_set:process dyntransition; # setcon
 
+# Grant access to seapp_contexts files
+# To be replaced by seapp_contexts_file label from commit 1e149967a
+allow runas rootfs:file r_file_perms;
+
 ###
 ### neverallow rules
 ###