Merge pull request #1007 from apache/cortlepp/remove-empty-clustering-guide

chore: remove empty clustering files (#AXIS2-6097)
diff --git a/modules/kernel/src/org/apache/axis2/deployment/ClusterBuilder.java b/modules/kernel/src/org/apache/axis2/deployment/ClusterBuilder.java
deleted file mode 100644
index e69de29..0000000
--- a/modules/kernel/src/org/apache/axis2/deployment/ClusterBuilder.java
+++ /dev/null
diff --git a/src/site/xdoc/docs/clustering-guide.xml b/src/site/xdoc/docs/clustering-guide.xml
deleted file mode 100644
index e69de29..0000000
--- a/src/site/xdoc/docs/clustering-guide.xml
+++ /dev/null