Fix: remove extra Precondition constructor (#78)

Author: DonutEspresso

lib/restErrors.js

@@ -25,7 +25,6 @@ var CODES = {
     InvalidVersion: 400,
     MissingParameter: 409,
     NotAuthorized: 403,
-    PreconditionFailed: 412,
     RequestExpired: 400,
     RequestThrottled: 429,
     ResourceNotFound: 404,

test/index.js

@@ -489,7 +489,7 @@ describe('restify-errors node module.', function() {
             // no good way to verify we got all the constructors, so it's hard
             // coded for now.
             // 16 built-in RestError subclasses
-            assert.equal(_.size(restErrors), 16);
+            assert.equal(_.size(restErrors), 15);
 
             // ensure each one has a displayName that ends in 'Error'
             // then try to new up one of each.