ensure root path is usable

examples/companion_radio/MyMesh.cpp

@@ -1312,6 +1312,7 @@ void MyMesh::checkCLIRescueCmd() {
       
       // log each file and directory
       File root = _store->openRead(path);
+      if(root){
         File file = root.openNextFile();
         while (file) {
 
@@ -1330,6 +1331,7 @@ void MyMesh::checkCLIRescueCmd() {
           file = root.openNextFile();
 
         }
+      }
 
     } else if (memcmp(cli_command, "cat", 3) == 0) {