Enable this option to be able to SSH into executors created by the GCE plugin with a custom SSH key-pair.

Need to add an SSH private key to Global Credentials in Jenkins using the Credentials plugin. Also need to manually add the corresponding public key to executor image in corresponding user's authorized_keys file in /home/<user>/.ssh/authorized_keys.

Public key must be in format ssh-rsa <public-key> <credential-id> where the credential-id is the name given to the private key added in Global Credentials.