added lu busy null check

src/Business/lu-busy-business.js

                 }
                 for (var i = 0; i < groups.length; ++i) {
                     var group = luBusyBusiness.groups[groups[i]];
-                    --group.count;
-                    if (group.count == 0) {
-                        if (!luBusyBusiness.hasError(group)) {
-                            group.deferred.resolve(null);
-                        }
-                        else {
-                            group.deferred.resolve(null);
+                    if (group != null) {
+                        --group.count;
+                        if (group.count == 0) {
+                            if (!luBusyBusiness.hasError(group)) {
+                                group.deferred.resolve(null);
+                            }
+                            else {
+                                group.deferred.resolve(null);
+                            }
+                            group.deferred = null;
                         }
-                        group.deferred = null;
                     }
                 }
             };
                 }
                 for (var i = 0; i < groups.length; ++i) {
                     var group = luBusyBusiness.groups[groups[i]];
-                    --group.count;
-                    group.errors.push(error);
-                    if (group.count == 0) {
-                        group.deferred.resolve(null);
-                        group.deferred = null;
+                    if (group != null) {
+                        --group.count;
+                        group.errors.push(error);
+                        if (group.count == 0) {
+                            group.deferred.resolve(null);
+                            group.deferred = null;
+                        }
                     }
                 }
             };