Update to Apache httpclient 4.5.x

Many properties of the connection between Jenkins and Bitbucket server
can now be set as Java parameters. The list of the supported parameters
is available at
https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/impl/client/HttpClientBuilder.html

Additionally, many compiler warnings are fixed by removing obsolete code.

Original patch by Albertin Loic <[email protected]>

Author: proski

pom.xml

@@ -61,16 +61,6 @@
   </properties>
 
   <dependencies>
-    <dependency>
-      <groupId>commons-httpclient</groupId>
-      <artifactId>commons-httpclient</artifactId>
-      <version>3.1</version>
-    </dependency>
-    <dependency>
-      <groupId>commons-codec</groupId>
-      <artifactId>commons-codec</artifactId>
-      <version>1.10</version>
-    </dependency>
     <dependency>
       <groupId>org.jenkins-ci.plugins</groupId>
       <artifactId>jackson2-api</artifactId>