Remove QtAlgorithms usage from QtXmlPatterns.

QtAlgorithms is getting deprecated,
see http://www.mail-archive.com/development@qt-project.org/msg01603.html

Change-Id: I4e2c7bf7970ba59ca9443c545b66db9f509d946b
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>