D13218: Draw FrameSVG corners only if both borders in both directions are enabled

[Vlad Zagorodniy]

zzag added a reviewer: Frameworks.

REPOSITORY
  R242 Plasma Framework (Library)

REVISION DETAIL
  https://phabricator.kde.org/D13218

To: zzag, #plasma, #frameworks
Cc: kde-frameworks-devel, michaelh, ngraham, bruns