fix "slapos/obs: Force gcc from slapos"

Setting max_version to 0 is less hacky. Also, it's not only for tarball
preparation, the package is created the same way.

component/slapos/obs.cfg

@@ -15,9 +15,7 @@ download-cache = download-cache
 
 [gcc]
 # force usage of gcc from slapos
-# it's required during tarball preparation, to have all dependencies
-# downloaded
-min_version = 1000
+max_version = 0
 
 # Uguu, upstream buildout.cfg must be patched as it works the other way
 # around from a packager point of view at least, thus at the end static