Security update to 4.2.8

The SMIME integration has led to www/rt42 being vulnerable to
shellshock related exploits.

Also contains minor fixes to Oracle DB schema updates from 4.2.7. No
changes for other RDBMS backends.

While here:

• Drop @dirrmtry from pkg-plist (mostly) and use @dir() to set the permissions on ${LOCALBASE}/etc/rt42/

Release Notes: http://bestpractical.com/release-notes/rt/4.2.8
MFH: 2014Q4
Security: 81e2b308-4a6c-11e4-b711-6805ca0b3d42