Fix QRegularExpression::wildcardToRegularExpression() usage

Summary:
It turns out that QRegularExpression::wildcardToRegularExpression() returns
an anchored (with \A and \z) pattern, so using anchoredPattern() in such
cases would actually anchor the pattern twice, which is obviously wrong.
Thanks to Mikołaj Płomieński (blaze) for catching it in
https://phabricator.kde.org/D26205#594891

Test Plan: make && ctest

Reviewers: Frameworks, dfaure

Reviewed By: dfaure

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D26692