mge-xml: fix compile-time warnings, versioning
Fix erroneous status in HP/Compaq SNMP MIB

Using the most recent HP firmware (1.76), erroneous on-battery status
were reported. Also disable an erroneous low-battery definition
(pointing nowhere), while waiting for actual improvements (report and
patch from Philippe Andersson ; Closes networkupstools/nut#117)
Update for release 2.7.2

Complete the release information for NUT 2.7.2
Add MGE information on USB-RJ45 cable

These information were provided by MGE years ago, and were waiting for
counter testing. Martin De Graaf - Loyer has now fixed this.
Note that the matching illustration will be committed on the new
nut-website repository
Add MGE information on USB-RJ45 cable

The illustration matching the previous commit was still needed on the
nut repository, and not on the nut-website on
docs: add mge-usb-rj45.jpg to distribution
docs: add Void Linux in download/Binary packages

Reference: https://github.com/networkupstools/nut/issues/125