source_webdav_update_properties_from_soup_uri: Ignore empty user name
source_webdav_update_properties_from_soup_uri: Ignore empty user name

Do not overwrite stored user name, when the set SoupURI doesn't have
user name set.

tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server