Fix appdata.xml problems
    
    The package installed two appdata.xml files: One was available from
    upsteam in folder _metainfo_ and was installed as-is. Another was
    created inline by the spec file and installed to _appdata_ folder. Since
    upstream appdata is available, the spec file version is removed
    as not needed. Filename of the upstream appdata is patched to comply
    with Fedora Packaging Guidelines section AppData
    (https://docs.fedoraproject.org/en-US/packaging-guidelines/AppData/).
    AppData check required by the guidelines is added.
    
    Also moved from %setup to %autosetup to get the patch handled easily.