Remove redundant SSL Socket Factory set

According to [1] value gets overwritten anyway when set through
setConnectionManager(customConnectionManager()).
As a result sslSocketFactory member was removed. It is not needed
anymore.

[1]
https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/impl/client/HttpClientBuilder.html#setSSLSocketFactory(org.apache.http.conn.socket.LayeredConnectionSocketFactory)
Change-Id: If698199e73817e8bfdd9672898e960ce9e196522
Signed-off-by: Jacek Centkowski <jcentkowski@collab.net>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/webhooks/HttpClientProvider.java b/src/main/java/com/googlesource/gerrit/plugins/webhooks/HttpClientProvider.java
index 3cbbe2a..7ba0a3a 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/webhooks/HttpClientProvider.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/webhooks/HttpClientProvider.java
@@ -49,18 +49,15 @@
   private static final int MAX_CONNECTION_INACTIVITY = 10000;
 
   private final Configuration cfg;
-  private final SSLConnectionSocketFactory sslSocketFactory;
 
   @Inject
   HttpClientProvider(Configuration cfg) {
     this.cfg = cfg;
-    this.sslSocketFactory = buildSslSocketFactory();
   }
 
   @Override
   public CloseableHttpClient get() {
     return HttpClients.custom()
-        .setSSLSocketFactory(sslSocketFactory)
         .setConnectionManager(customConnectionManager())
         .setDefaultRequestConfig(customRequestConfig())
         .setServiceUnavailableRetryStrategy(customServiceUnavailRetryStrategy())
@@ -110,7 +107,7 @@
   private HttpClientConnectionManager customConnectionManager() {
     Registry<ConnectionSocketFactory> socketFactoryRegistry =
         RegistryBuilder.<ConnectionSocketFactory>create()
-            .register("https", sslSocketFactory)
+            .register("https", buildSslSocketFactory())
             .register("http", PlainConnectionSocketFactory.INSTANCE)
             .build();
     PoolingHttpClientConnectionManager connManager =