VFS-824 Fix HttpFileSystem free Unused Resources lead to HttpClient Connection Pool Shutdown

Option Two：Share ConnectionManager.

Author: xieyuliang

commons-vfs2/src/main/java/org/apache/commons/vfs2/provider/http4/Http4FileProvider.java

@@ -206,6 +206,7 @@ protected HttpClientBuilder createHttpClientBuilder(final Http4FileSystemConfigB
         final HostnameVerifier hostNameVerifier = createHostnameVerifier(builder, fileSystemOptions);
         final HttpClientBuilder httpClientBuilder =
                 HttpClients.custom()
+                .setConnectionManagerShared(true)
                 .setRoutePlanner(createHttpRoutePlanner(builder, fileSystemOptions))
                 .setConnectionManager(createConnectionManager(builder, fileSystemOptions, sslContext, hostNameVerifier))
                 .setSSLContext(sslContext)