[ZEPPELIN-3243] fix IndexOutOfBoundsException when 'No interpreter is…

… binded to this note'

### What is this PR for?
I observed IndexOutOfBoundsException when using zeppelin locally on an existing notebook repository and with fresh interpreter.json file.
The default Zeppelin behavior when using existing notebooks is the manual binding of the interpreter settings, which works fine. This PR simply avoids the IndexOutOfBoundsException.

### What type of PR is it?
Bug Fix

### Todos
-

### What is the Jira issue?
[https://issues.apache.org/jira/browse/ZEPPELIN-3243](https://issues.apache.org/jira/browse/ZEPPELIN-3243)

### How should this be tested?
- manual

### Screenshots (if appropriate)

### Questions:
* Does the licenses files need update? no
* Is there breaking changes for older versions? no
* Does this needs documentation? no

Author: Andreas Weise <a.weise@avm.de>

Closes apache#2808 from weand/ZEPPELIN-3243 and squashes the following commits:

b97a38e [Andreas Weise] ZEPPELIN-3243 fix IndexOutOfBoundsException when 'No interpreter is binded to this note'

zeppelin-zengine/src/main/java/org/apache/zeppelin/interpreter/InterpreterSettingManager.java

@@ -412,7 +412,8 @@ private void registerInterpreterSetting(List<RegisteredInterpreter> registeredIn
 
   @VisibleForTesting
   public InterpreterSetting getDefaultInterpreterSetting(String noteId) {
-    return getInterpreterSettings(noteId).get(0);
+    List<InterpreterSetting> allInterpreterSettings = getInterpreterSettings(noteId);
+    return allInterpreterSettings.size() > 0 ? allInterpreterSettings.get(0) : null;
   }
 
   public List<InterpreterSetting> getInterpreterSettings(String noteId) {
@@ -468,7 +469,7 @@ public Map<String, Object> getEditorSetting(Interpreter interpreter, String user
           group = replNameSplit[0];
         }
         // when replName is 'name' of interpreter
-        if (defaultSettingName.equals(intpSetting.getName())) {
+        if (intpSetting.getName().equals(defaultSettingName)) {
           editor = intpSetting.getEditorFromSettingByClassName(interpreter.getClassName());
         }
         // when replName is 'alias name' of interpreter or 'group' of interpreter