drivers : fix possible memory leak.

In arguments parsing, if user option is passed.
drivers : add Liebert GXT3 device.
HCL: Rucelf UPOII-3000-96-EL supported by blazer_ser

Manufacturer: http://www.rucelf.ua/en/catalog/upoii-3000-96-el/

Closes: https://github.com/networkupstools/nut/issues/165
Merge branch 'Liebert_GXT3_0008'

Reference: http://news.gmane.org/find-root.php?message_id=7056332.1066111.1412937856080.JavaMail.www%40wsfrf1124