remove appdomain's ability to examine all of /proc

Remove the CTS specific rule which allows appdomain processes
to view /proc entries for the rest of the system. With this change,
an SELinux domain will only be able to view it's own /proc
entries, e.g. untrusted_app can only view /proc entries for other
untrusted_app, system_app can only view /proc entries for other
system_apps, etc.

/proc contains sensitive information, and we want to avoid
leaking this information between app security domains.

Bug: 17254920
Change-Id: I59da37dde00107a5ab123df3b79a84afa855339f