Allow OCG binaries to send/receive signals (AppArmor fixes).

Allow the OCG binaries to send/receive signals, which is used to prevent
DoS attempts by limiting the execution time of subprocesses.

Also allow rsvg-convert to read /usr/share/libthai/ (found in the
apparmor deny logs).

Change-Id: Ia6d53540ca36d60344c7c27e766c1d82b421f7bf
Merge "Allow OCG binaries to send/receive signals (AppArmor fixes)." into production