Small fix for feature allowing ShortId on any field
Small fix for feature allowing ShortId on any field

defaultSave was called for every iteration on the for fieldName in this.schema.tree. Fixed by pulling defaultSave out of the for loop.
From https://github.com/jjwchoy/mongoose-shortid/commit/5c6f7bfafb48c60c1abcc5d8b59be1b14a373ab1
leeroybrun/mongoose-shortid-nodeps,hiconversion/mongoose-shortid-nodeps