Remove broken "libcloud" and "siptester" recipes

This code seems not used, before https://lab.nexedi.com/nexedi/slapos/commit/51c3773e3a4a621959af6445c8f164688af026c1 and https://lab.nexedi.com/nexedi/slapos/commit/b77d7baef29c5c798790b0ed417eb581d7a26236 it was not possible to import.