Fix include warning related to qtpositioningglobal.h

This was already fixed in stable but for some reason was not carried over to
dev during the merges.

Change-Id: I2e7c8fe6d11e58c4070ebb03d0f8928e7c47b7cf
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Erik Mattsson <erik.mattsson@appello.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>