Fixes QTIFW-322, missing magic cookie in installer binary

* on mac magic cookie is kept in install.dat and not in installer binary itself

Change-Id: I568bbdf7a0bcf3b6efeda0bdfe2141e15c6c73aa
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
Merge remote-tracking branch 'origin/1.3' into 1.4

Change-Id: Ie74dcebe9412da0caceec9f541eb51ad46bfea9f