D25440: Set a proper agent string for Attica requests

[Dan Leinir Turthra Jensen]

leinir added a reviewer: ronaldv.

REPOSITORY
  R235 Attica

REVISION DETAIL
  https://phabricator.kde.org/D25440

To: leinir, #frameworks, #knewstuff, #plasma, starbuck, ronaldv
Cc: kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns