fix(workbenchRoutes): recent qriRefs adjusted correctly

Previously, each newly added history ref was reseting the edit ref, and each edit ref was reseting the history ref.

Ensure that empty values don't muck up the logic.

app/reducers/workbenchRoutes.ts

@@ -25,8 +25,8 @@ export const WORKBENCH_ROUTES_CLEAR = 'WORKBENCH_ROUTES_CLEAR'
 export default (state = initialState, action: AnyAction) => {
   switch (action.type) {
     case WORKBENCH_ROUTES_HISTORY_REF:
-      if (state.historyRef.username !== action.qriRef.username ||
-        state.historyRef.name !== action.qriRef.name) {
+      if ((state.historyRef.username !== '' && state.historyRef.username !== action.qriRef.username) ||
+        (state.historyRef.name !== '' && state.historyRef.name !== action.qriRef.name)) {
         return {
           ...initialState,
           historyRef: action.qriRef,
@@ -39,8 +39,8 @@ export default (state = initialState, action: AnyAction) => {
         location: action.qriRef.location
       }
     case WORKBENCH_ROUTES_EDIT_REF:
-      if (state.editRef.username !== action.qriRef.username ||
-        state.editRef.name !== action.qriRef.name) {
+      if ((state.editRef.username !== '' && state.editRef.username !== action.qriRef.username) ||
+        (state.editRef.name !== '' && state.editRef.name !== action.qriRef.name)) {
         return {
           ...initialState,
           editRef: action.qriRef,