Revert "update jackrabbit webdav lib to version 2.6.3"

This reverts commit 44acb753ef34fa40f31d74818341955f2816ec15.

pom.xml

@@ -49,7 +49,7 @@
         <dependency>
             <groupId>org.apache.jackrabbit</groupId>
             <artifactId>jackrabbit-webdav</artifactId>
-            <version>2.6.3</version>
+            <version>2.5.2</version>
         </dependency>
 
     </dependencies>