Ant buildscript should not check for explicit Ant version numbers

Committed r11768 as a bandaid to support ant 1.8 . Necessary to get it building on our new build farm, I think. re)

http://www.mail-archive.com/rpm-users@rpm5.org/msg00079.html

Removing the 'fix version' for all unresolved issues that were scheduled for version 7.8.2. We're releasing this version today - the remaining issues should be rescheduled later.

So, we will have to release "bandaid" fixes with every new Ant version.

We'll likely replace Ant with Maven starting from Openfire 4.x.

Created a PR for this here: https://github.com/igniterealtime/Openfire/pull/296

Sadly, the same cannot be done (easily) for Java version. I added Java 1.9 to be somewhat future proof for a while.

Note that this commit also raises the minimum version of Ant from 1.6 (released in 2003/2004) to 1.7.1 (released: 2008) (the Ant version check itself was added in 1.7).