fix: exit server after reconfiguring

According to [the docs][1], `exitOnUncaughtException` should:

> Exit the process after handling an uncaught exception. Requires
> `captureUncaught` to also be set.

So with this config:

````js
var rollbar = new Rollbar({
  captureUncaught: true,
  exitOnUncaughtException: true,
  // ...
});
```

...an uncaught exception should exit the process.

This works correctly, but *only* if `rollbar.configure()` is *never*
called again, because:

 1. `exitOnUncaughtException` [was deleted][2] from our options
 2. Calling `configure()` calls [`setupUnhandledCapture()`][3]...
 3. ...which calls [`handleUncaughtExceptions()`][4]...
 4. ...which now [tries to access][5] `options.exitOnUncaughtException`
 5. But this option was deleted in Step 1, so when we [replace][6] our
    `uncaughtException` handler, we now have `exitOnUncaught = false`

This change:

 - no longer deletes `exitOnUncaughtException` from options (it's
   unclear why this is the only option that is deleted)
 - directly accesses `options.exitOnUncaughtException` in the
   handler, just like `options.captureUncaught` is accessed directly

[1]: https://docs.rollbar.com/docs/rollbarjs-configuration-reference#context-1
[2]: https://github.com/rollbar/rollbar.js/blob/e964ecbdb16a4d2b8b5feaa8b70a2ec327648ed0/src/server/rollbar.js#L587
[3]: https://github.com/rollbar/rollbar.js/blob/e964ecbdb16a4d2b8b5feaa8b70a2ec327648ed0/src/server/rollbar.js#L118
[4]: https://github.com/rollbar/rollbar.js/blob/e964ecbdb16a4d2b8b5feaa8b70a2ec327648ed0/src/server/rollbar.js#L578
[5]: https://github.com/rollbar/rollbar.js/blob/e964ecbdb16a4d2b8b5feaa8b70a2ec327648ed0/src/server/rollbar.js#L586
[6]: https://github.com/rollbar/rollbar.js/blob/e964ecbdb16a4d2b8b5feaa8b70a2ec327648ed0/src/server/rollbar.js#L589

Author: alecgibson

src/server/rollbar.js

@@ -583,9 +583,6 @@ Rollbar.prototype.setupUnhandledCapture = function () {
 };
 
 Rollbar.prototype.handleUncaughtExceptions = function () {
-  var exitOnUncaught = !!this.options.exitOnUncaughtException;
-  delete this.options.exitOnUncaughtException;
-
   addOrReplaceRollbarHandler('uncaughtException', function (err) {
     if (!this.options.captureUncaught && !this.options.handleUncaughtExceptions) {
       return;
@@ -597,7 +594,7 @@ Rollbar.prototype.handleUncaughtExceptions = function () {
         logger.error(err);
       }
     });
-    if (exitOnUncaught) {
+    if (this.options.exitOnUncaughtException) {
       setImmediate(function () {
         this.wait(function () {
           process.exit(1);

test/server.rollbar.test.js

@@ -550,6 +550,38 @@ vows.describe('rollbar')
                   assert.equal(logStub.getCall(0).args[0].err.message, 'node error');
                 }
                 notifier.log.restore();
+              },
+              'exitOnUncaughtException': {
+                topic: function () {
+                  var rollbar = new Rollbar({
+                    accessToken: 'abc123',
+                    captureUncaught: true,
+                    exitOnUncaughtException: true
+                  });
+                  rollbar.exitStub = sinon.stub(process, 'exit');
+
+                  nodeThrow(rollbar, this.callback);
+                },
+                'should exit': function (r) {
+                  var calls = r.exitStub.getCalls();
+                  r.exitStub.restore();
+                  assert.equal(calls.length, 1);
+                },
+                'unrelated option reconfigured': {
+                  topic: function(r) {
+                    r.configure({
+                      environment: 'new-env'
+                    });
+                    r.exitStub = sinon.stub(process, 'exit');
+
+                    nodeThrow(r, this.callback);
+                  },
+                  'should exit': function(r) {
+                    var calls = r.exitStub.getCalls();
+                    r.exitStub.restore();
+                    assert.equal(calls.length, 1);
+                  }
+                }
               }
             }
           }