Don't set lastEventId if Raven is not configured (fixes #828)

Author: benvinegar

src/raven.js

@@ -1396,6 +1396,8 @@ Raven.prototype = {
         var self = this;
         var globalOptions = this._globalOptions;
 
+        if (!this.isSetup()) return;
+
         // Send along an event_id if not explicitly passed.
         // This event_id can be used to reference the error within Sentry itself.
         // Set lastEventId after we know the error should actually be sent
@@ -1406,8 +1408,6 @@ Raven.prototype = {
 
         this._logDebug('debug', 'Raven about to send:', data);
 
-        if (!this.isSetup()) return;
-
         var auth = {
             sentry_version: '7',
             sentry_client: 'raven-js/' + this.VERSION,