Run extra command if defined

Change-Id: I7d6aa4fe0cb3011fb92485a32ecabd8849018e13
diff --git a/deploy-k8s-deployments.groovy b/deploy-k8s-deployments.groovy
index fc33f5b..5a0bf9d 100644
--- a/deploy-k8s-deployments.groovy
+++ b/deploy-k8s-deployments.groovy
@@ -19,6 +19,20 @@
     }
     stage("Update components") {
         common.infoMsg("Setting up components..")
+        def extraCommand
+        try {
+            extraCommand = EXTRA_COMMAND
+        } catch (Throwable e) {
+            extraCommand = null
+        }
+
+        if (extraCommand) {
+            salt.cmdRun(
+                saltMaster,
+                targetExpression,
+                extraCommand
+            )
+        }
         out = salt.cmdRun(
             saltMaster,
             targetExpression,