When a plugin fails to update for what ever reason, it calls the [error helper method](https://github.com/mortardata/mortar/blob/f251d7d53898f9981aed5214f7f331c0bb52eeb3/lib/mortar/plugin.rb#L141). The error helper method prints the error then exits. This is the desired behaviour of the error function, but in this case, if one plugin fails to update we should log the error in proper format, but continue updating the rest of the plugins.