CMakePM: Always create build directories

Having two configurations for a project, one in /tmp and one in the
right build directory is confusing and for big projects can take some
time.

Fixes: QTCREATORBUG-25532
Change-Id: Ib0dad267117b3c025d668646ef076b0f77bff166
Reviewed-by: hjk <hjk@qt.io>

src/plugins/cmakeprojectmanager/builddirparameters.h

@@ -54,7 +54,6 @@ public:
 
     Utils::FilePath sourceDirectory;
     Utils::FilePath buildDirectory;
-    Utils::FilePath workDirectory; // either buildDirectory or a QTemporaryDirectory!
     QString cmakeBuildType;
 
     Utils::Environment environment;