Adapt set-credentials to new constructor

Use the new constructor of the credentials implementation
so that .netrc would be correctly loaded into
a the Jenkins credentials vault.

Change-Id: Ifc5eb46bffaf61fbc5d99aa5dadce6c48a6370a5
diff --git a/jenkins-docker/master/set-credentials.groovy b/jenkins-docker/master/set-credentials.groovy
index cfaec7b..6459ed9 100644
--- a/jenkins-docker/master/set-credentials.groovy
+++ b/jenkins-docker/master/set-credentials.groovy
@@ -23,7 +23,7 @@
     def user = lineParts[3]
     def pass = lineParts[5]
     println "Setting password for user $user on machine $machine"
-    Credentials c = (Credentials) new UsernamePasswordCredentialsImpl(machine, ".netrc credentials for $machine", user, pass)
+    Credentials c = (Credentials) new UsernamePasswordCredentialsImpl(CredentialsScope.GLOBAL, machine, ".netrc credentials for $machine", user, pass)
     SystemCredentialsProvider.getInstance().getStore().addCredentials(Domain.global(), c)
   }
 }