Rip out duplicate white space from Qt configure options

When building Qt for Installer-Framework ensure no duplicate white
space exists in options string.

Change-Id: Ia0c5d757aa229b2b494d7f6b5d386644c02768e9
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>