Qmake: Re-parse project after changing the build directory

That is necessary so that the executables get updated.

Task-number: QTCREATORBUG-10107
Change-Id: I42e3ce38a5824e285546c43a3ec0045b090c6af5
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Qmake: Do not have qmake config change build directory

Change-Id: I538b4576490d62f3c1f8555fdeffdafecf797e7a
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Qmake: Rename emitBuildDirectoryChanged()

The method is used to reset the build directory if shadow building
becomes unavailable due to the Qt version changing. It does not
explicitly emit anything anymore.

Change-Id: I27b46b77f334be62f4db5f269529f8a2d62d834b
Reviewed-by: Daniel Teske <daniel.teske@digia.com>