0.9.10 does not call 'error' callback in Model#save on validation error

[Derbeth]

From my understanding of Model#save() documentation, when save() is started, either 'success' or 'error' callback should be called.

This is true in Backbone 0.9.9:
http://jsfiddle.net/derbeth/vs3Zb/4/

but not in Backbone 0.9.10:
http://jsfiddle.net/derbeth/tGASS/3/

I know you have changed when validation is fired, but the Model#save() documentation still says:

   The error callback will also be invoked if the model has a validate method, and validation fails.

[caseywebdev]

See my explanation in #2153