refresh highlight-3 patch
    
    The patch to default to highlight-3 applied with a bit of an offset.
    On EL7 this causes a .orig file to be created.  This is then copied into
    the filter dir by the cgit install process.
    
    Rebase the patch on the current cgit to avoid this bit of cruft.
    
    Alternately (or additionally), we could add `--no-backup-if-mismatch` to
    the %_default_patch_flags macro for EL7 builds.  This flag is set in
    newer Fedora and EL releases.