deal with null currentConfig

My mergeConfig kept complaining about a null currentConfig.  Not sure if currentConfig is ever supposed to be null, but it's happening to me.  Using this allowed it to carry on.  This was with a new grails 2.3.4 app, springsecuritycore plugin and Facebook and openId plugins.
Merge pull request #34 from mgkimsal/patch-1

deal with null currentConfig