Log Parse Errors so they are intelligible. (#3431)

The problem this pr is trying to solve:

When an error occurs on the server, a message should
be returned to the client, and a message should be logged.

Currently, on the server, the log is just [object, object]

This pr will stop calling the default express error handler
which causes two problems: 1. it writes to console instead of log file
2. the output is completely useless! :)

Instead, we'll log the error ourselves using the ParseServer's logger.

fixes: #661

spec/CloudCodeLogger.spec.js

@@ -194,7 +194,7 @@ describe("Cloud Code Logger", () => {
     Parse.Cloud.run('aFunction', { foo: 'bar' })
             .then(null, () => logController.getLogs({ from: Date.now() - 500, size: 1000 }))
             .then(logs => {
-              const log = logs[1];
+              const log = logs[2];
               expect(log.level).toEqual('error');
               expect(log.message).toMatch(
                     /Failed running cloud function aFunction for user [^ ]* with:\n {2}Input: {"foo":"bar"}\n {2}Error: {"code":141,"message":"it failed!"}/);