修正me.chanjar.weixin.common.util.http.DefaultApacheHttpClientBuilder#prepare调用问题，try to fix#52

Author: ben

weixin-java-common/src/main/java/me/chanjar/weixin/common/util/http/DefaultApacheHttpClientBuilder.java

@@ -58,9 +58,8 @@ public boolean retryRequest(IOException exception, int executionCount, HttpConte
 
   private HttpClientBuilder httpClientBuilder;
 
-  private boolean prepared = false;
-
   private DefaultApacheHttpClientBuilder() {
+    prepare();
   }
 
   public static DefaultApacheHttpClientBuilder get() {
@@ -153,11 +152,6 @@ private void prepare() {
 
   @Override
   public CloseableHttpClient build() {
-    if (!this.prepared) {
-      prepare();
-      this.prepared = true;
-    }
-
     return this.httpClientBuilder.build();
   }