'Populate the _preconfigs dictionary entry for the preconfig described
by the given parameters.  If the preconfig has already been loaded,
do nothing.
name: specific name of the preconfig
type: \'metrics\' or \'qual\''

def _read_preconfig(self, name, type):

    if (self._preconfigs[type][name] is not None):
        return
    self._preconfigs[type][name] = {}
    path = self._get_preconfig_path([type, name])
    config = open(path)
    try:
        for line in config:
            parts = line.split(':')
            self._preconfigs[type][name][parts[0]] = parts[1].strip()
    finally:
        config.close()
