fix #59, createOffer missing err callback

dist/peer.js

@@ -1836,6 +1836,9 @@ ConnectionManager.prototype._makeOffer = function() {
       self.emit('error', err);
       util.log('Failed to setLocalDescription, ', err);
     });
+  }, function(err) {
+    self.emit('error', err);
+    util.log('Failed to createOffer, ', err);
   });
 };
 

lib/connectionmanager.js

@@ -166,6 +166,9 @@ ConnectionManager.prototype._makeOffer = function() {
       self.emit('error', err);
       util.log('Failed to setLocalDescription, ', err);
     });
+  }, function(err) {
+    self.emit('error', err);
+    util.log('Failed to createOffer, ', err);
   });
 };