Fixed issue with has_children where it thought a block was being passed instead of a empty hash parameter.
Fixed issue with has_children where it thought a block was being passed instead of a empty hash parameter.

skyeagle/mongoid-ancestry,hotvulcan/ancestry,WebEnrich/mongoid-ancestry,antstorm/ancestry,tjchambers/ancestry,shaggyone/ancestry,macat/ancestry,stefankroes/ancestry,kbrock/ancestry