BehaviorSubject getValue() better to check for errors using .hasError field rather than checking .error field for null/undefined.

Author: gordey4doronin

src/core/subjects/behaviorsubject.js

@@ -43,7 +43,7 @@
        */
       getValue: function () {
           checkDisposed(this);
-          if (this.error) {
+          if (this.hasError) {
               throw this.error;
           }
           return this.value;