Bug#847365: Don't build depend on libkf5config-bin on stage1

[Александр Волков]

Package: libproxy
Version: 0.4.13-1.1

There is a circular dependency: libproxy -> kconfig -> 
qtbase-opensource-src -> libproxy
Don't build depend on libkf5config-bin when the profile stage1 is active 
to break it.