AMBARI-17952. Add nimbus.impersontation.acl on upgrade - remove extra new line causing parsing issue (smohanty)

ambari-server/src/main/resources/stacks/HDP/2.3/upgrades/nonrolling-upgrade-2.5.xml

@@ -1,4 +1,3 @@
-
 <?xml version="1.0"?>
 <!--
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