Fix HTTP proxy settings
Summary:
After SlaveBase::config() was replaced with SlaveBase::mapConfig()
the reading of "ProxyUrls" value had beed broken as QVariant with
type QByteArray can't be directly converted to QStringList.
It should be converted to QString and splitted.
Reviewers: Frameworks, meven
Reviewed By: meven
Subscribers: meven, kde-frameworks-devel
Tags: Frameworks
BUG: 414346
FIXED-IN: 5.65
Differential Revision: https://phabricator.kde.org/D25432