OAK-829: ConstraintViolationException while retrieving definition for all nodes with name jcr:childNodeDefinition

Drop the possible SNS index from a node name when accessing the node definition

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1484689 13f79535-47bb-0310-9956-ffa450edef68