Add client secret getter for Jelly (#61)

Author: zbynek

src/main/java/org/jenkinsci/plugins/GitLabSecurityRealm.java

@@ -60,7 +60,6 @@
 import org.gitlab.api.models.GitlabUser;
 import org.jfree.util.Log;
 import org.kohsuke.stapler.DataBoundConstructor;
-import org.kohsuke.stapler.DataBoundSetter;
 import org.kohsuke.stapler.Header;
 import org.kohsuke.stapler.HttpRedirect;
 import org.kohsuke.stapler.HttpResponse;
@@ -258,6 +257,14 @@ public String getClientID() {
         return clientID;
     }
 
+    /**
+     * Used by jelly
+     * @return the client secret
+     */
+    public Secret getClientSecret() {
+        return clientSecret;
+    }
+
     // "from" is coming from SecurityRealm/loginLink.jelly
     public HttpResponse doCommenceLogin(StaplerRequest request, @QueryParameter String from, @Header("Referer") final String referer) throws IOException {
         // 2. Requesting authorization :