Fix credentials and ssh-credentials version

Fix credentials and ssh-credentials version

updaed these plugins which casued

ssh-credentials-plugin.BasicSSHUserPrivateKey.UsersPrivateKeySource

method to fail

def gerrit_credentials = new BasicSSHUserPrivateKey(
  CredentialsScope.GLOBAL,
  "ciworkshop-jenkins-ssh", // ID
  "jenkins-workshop", // username
  private_key_on_master,
  null, // password
  "Gerrit User" // description
)

The option to add a key: From the Jenkins master ~/.ssh
is gone in the new version

Change-Id: Iad4c1e12b45ca8d4205ab3d2109cfe19163a797d
Signed-off-by: Aric Gardner <agardner@linuxfoundation.org>