Don't invoke qstring localized stuff in critical section

Summary:
Move the DrKonqi socket name generation out of the signal handler, since it can freeze while locking QTextCodec mutexes

Signed-off-by: Jiří Paleček <jpalecek@web.de>

Reviewers: Frameworks, dfaure

Reviewed By: dfaure

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D29809