fix global leak from dirty refactor

Author: ryanflorence

lib/stores/route-store.js

@@ -167,8 +167,8 @@ function extractQuery(activePath) {
  * Along the way, the given _routes array is populated with <Route> objects that
  * are parents of the matching route, in the order they appear in the tree.
  */
-function findActiveParams(_activePath, tree, _routes) {
-  activePath = _activePath.replace(queryMatcher, '');
+function findActiveParams(activePath, tree, _routes) {
+  activePath = activePath.replace(queryMatcher, '');
   return findFirst(tree, function (node) {
     var params = path.extractParams(node.computedPath, activePath);