Ignore files generated by the pom version update plugin

Change-Id: I0e96de2a26fd61b4f073cb6e03aba6254968334c
diff --git a/tools/build/onos-validate-change-version.excludes b/tools/build/onos-validate-change-version.excludes
index 86c79e5..57f57fb 100755
--- a/tools/build/onos-validate-change-version.excludes
+++ b/tools/build/onos-validate-change-version.excludes
@@ -2,6 +2,7 @@
 \./.git
 /target/
 \.iml$
+\.versionsBackup$
 \./buck-out/
 \./\.buckd
 \./lib/BUCK