Return version text and collect if not collected.

def version_text(self):
        """Return version text and collect if not collected."""
        if self._version_text is None:
            self.chain.connection.log("Collecting version information")
            self._version_text = self.driver.get_version_text()
            if self._version_text:
                self.chain.connection.log("Version info collected")
            else:
                self.chain.connection.log("Version info not collected")

        return self._version_text