ProjectManager: Simplify Project::setBuildSystemCreator()

Make it a template method.

Change-Id: I3f0510c89d7f0bfe2f814dadc4d8de01c0e1cc89
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/autotoolsprojectmanager/autotoolsprojectplugin.cpp

@@ -44,7 +44,7 @@ public:
 
         setHasMakeInstallEquivalent(true);
 
-        setBuildSystemCreator([](Target *t) { return new AutotoolsBuildSystem(t); });
+        setBuildSystemCreator<AutotoolsBuildSystem>();
     }
 };