Drop obsolete functions
    
    These functions are now completely unused.
    
    They were overridden from pyrpkg to use our client-side and custom CA
    certificates.
    
    However, pyrpkg now handles that on its own with its new
    pyrpkg.lookaside module, all we need to do in fedpkg is define our
    fedpkg.Commands.cert_file and fedpkg.Commands.ca_cert properties...
    which we've been doing since forever already.
    
    Signed-off-by: Mathieu Bridon <bochecha@daitauha.fr>