[arch-general] dropping OpenJDK6 by the end of this month

We will remove the OpenJDK6 packages by the end of this month. All users should move to OpenJDK7 based packages jre7-openjdk/jre7-openjdk-headless/jdk7-openjdk (or the Oracle based JRE/JDK from AUR) very soon. The next OpenJDK7 update will replace openjdk6 on your system. -Andy