Allow OCG to read the contents of its output/temp/postmortem directories.

Apparmor was allowing OCG to create files underneath these directories,
but throwing EACCESS when the OCG garbage collector attempted to readdir
the directory itself.

Change-Id: I026c374eadfd2b3623d7d11b3a8d82d17bcac49b
Merge "Allow OCG to read the contents of its output/temp/postmortem directories." into production