private UserGroupInformation getUserGroupInformation() throws IOException {
        if (userGroupInformation == null) {
            userGroupInformation = buildRemoteUser(Optional.ofNullable(runAsUser));
        }

        return userGroupInformation;
    }
HDFS does not support some chars in its dir/filenames so need to clean
them here

@param path The path to clean
@return A cleaned path
stroom-pipeline/src/main/java/stroom/pipeline/writer/HDFSFileAppender.java