RATIS-2194. FileLock didn't unlock properly (#1183)

Author: chungen0126

ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerProxy.java

@@ -416,6 +416,13 @@ private void startImpl() throws IOException {
   public void close() {
     lifeCycle.checkStateAndClose(() -> {
       LOG.info("{}: close", getId());
+
+      try {
+        ConcurrentUtils.shutdownAndWait(implExecutor.get());
+      } catch (Exception ignored) {
+        LOG.warn(getId() + ": Failed to shutdown implExecutor", ignored);
+      }
+
       impls.close();
 
       try {
@@ -430,12 +437,6 @@ public void close() {
         LOG.warn(getId() + ": Failed to close " + SupportedDataStreamType.NETTY + " server", ignored);
       }
 
-      try {
-        ConcurrentUtils.shutdownAndWait(implExecutor.get());
-      } catch (Exception ignored) {
-        LOG.warn(getId() + ": Failed to shutdown implExecutor", ignored);
-      }
-
       try {
         ConcurrentUtils.shutdownAndWait(executor.get());
       } catch (Exception ignored) {