Verify formatting using GJF 1.7

Change I216f69ea set the default formatting version to GJF 1.24.0,
however older branches are still formatted with GJF 1.7.

Explicitly set the GJF version to 1.7 so that we can still have
successful validation for older branches.

Change-Id: I180d68cee70c7351d2ffbaaf1fc84eb1e0047907

Jenkinsfile

diff --git a/Jenkinsfile b/Jenkinsfile
index b1692ff..6ee14c4 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -1,3 +1,4 @@
 pluginPipeline(formatCheckId: 'gerritforge:plugins-aws-dynamodb-refdb-code-style',
                 buildCheckId: 'gerritforge:plugins-aws-dynamodb-refdb-build-test',
-                extraModules: [ 'global-refdb' ])
+                extraModules: [ 'global-refdb' ],
+                gjfVersion: '1.7')