Reverting Hibernate Validator version to 5.1.1.Final

git-svn-id: https://svn.apache.org/repos/asf/syncope/branches/1_2_X@1622202 13f79535-47bb-0310-9956-ffa450edef68
Merge from 1_2_X

git-svn-id: https://svn.apache.org/repos/asf/syncope/trunk@1622203 13f79535-47bb-0310-9956-ffa450edef68