Upgrade to jclouds 2.4.0

Release notes:

https://jclouds.apache.org/releasenotes/2.4.0/

Fixes #338.

Author: gaul

pom.xml

@@ -316,7 +316,7 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <java.version>1.8</java.version>
-    <jclouds.version>2.3.0</jclouds.version>
+    <jclouds.version>2.4.0</jclouds.version>
     <slf4j.version>1.7.28</slf4j.version>
     <shade.prefix>${project.groupId}.shaded</shade.prefix>
     <surefire.version>2.20</surefire.version>