[ZEPPELIN-5624] Check if the path directory is compliant. (#4282)

* [ZEPPELIN-5624] Check if the path directory is compliant.
diff --git a/zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterSettingManager.java b/zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterSettingManager.java
index 6d30006..cfdae70 100644
--- a/zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterSettingManager.java
+++ b/zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterSettingManager.java
@@ -1035,12 +1035,11 @@
         // Cluster event accepting nodes do not need to save files repeatedly
         saveToFile();
       }
+      File localRepoPath = new File(conf.getInterpreterLocalRepoPath());
+      FileUtils.deleteDirectory(new File(localRepoPath, id));
       removed = true;
     }
 
-    File localRepoDir = new File(conf.getInterpreterLocalRepoPath() + "/" + id);
-    FileUtils.deleteDirectory(localRepoDir);
-
     return removed;
   }