Implement new method scriptRemoved(CompiledScript) in ScriptEngineService

This [PR](elastic/elasticsearch#8062) broke ScriptEngineService by adding a new method `scriptRemoved(CompiledScript)`.

Closes #29.

(cherry picked from commit 1fd05bc)

Author: dadoonet

src/main/java/org/elasticsearch/script/javascript/JavaScriptScriptEngineService.java

@@ -25,10 +25,7 @@
 import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.script.ExecutableScript;
-import org.elasticsearch.script.ScoreAccessor;
-import org.elasticsearch.script.ScriptEngineService;
-import org.elasticsearch.script.SearchScript;
+import org.elasticsearch.script.*;
 import org.elasticsearch.script.javascript.support.NativeList;
 import org.elasticsearch.script.javascript.support.NativeMap;
 import org.elasticsearch.script.javascript.support.ScriptValueConverter;
@@ -72,6 +69,11 @@ public void close() {
 
     }
 
+    @Override
+    public void scriptRemoved(@Nullable CompiledScript compiledScript) {
+        // Nothing to do here
+    }
+
     @Override
     public String[] types() {
         return new String[]{"js", "javascript"};