Fixed calligra crashing when opening remote document

Summary: BUG:358581

Test Plan: Example working print: calligrawords --print "https://www.oasis-open.org/committees/download.php/31049/UOML%20Sample.odt"

Reviewers: danders

Reviewed By: danders

Subscribers: anthonyfieroni, boemann, Calligra-Devel-list

Tags: #calligra:_3.0

Differential Revision: https://phabricator.kde.org/D18466