Don't BuildRequire pyflakes
    
    Linting code is extremely useful in upstream, but not so much in downstream.
    
    When we update Python to 3.N+1, linters are often broken for a while and pycurl
    is part of the initial Python bootstrap sequence.
    Not linting the code in %check allows us to rebuild pycurl without functional
    pyflakes. See https://bugzilla.redhat.com/show_bug.cgi?id=1831248