Workaround broken shebang due to rhbz#1335203
    
    536c139 ("Update to new packaging standards", 2018-12-09) exposed a bug
    in the %py2_build macros¹ which cause linkchecker to have a broken
    shebang.  The result is a script which cannot be run:
    
        $ linkchecker -h
        Unknown option: -
        usage: /usr/bin/python2 [option] ... [-c cmd | -m mod | file | -] [arg] ...
        Try `python -h' for more information.
    
    Fix this by patching the linkchecker script to remove the existing '-Ru'
    options and add them back via the %py2_shbang_opts macro.
    
    [Note: a patch is used rather than a simpler sed so that this will fail
    if/when the options are changed upstream, allowing us to notice when
    adjustments are required.]
    
    ¹ https://bugzilla.redhat.com/1335203