Wip/martyn/u boot installer

Jenkinsfile

@@ -614,7 +614,7 @@ buildCandidates.each { name, arch ->
 
 println("buildOnlyList:")
 println(buildOnlyList.keySet())
-if (buildOnlyList.containsKey("installers")) {
+if (buildOnlyList.keySet().contains("installers")) {
   /* Add installer */
   first_pass << [("$name $type"):
       buildInstallers(installers)