test: Add IdentitiesOnly to the ssh config example
test: Add IdentitiesOnly to the ssh config example

With the IdentitiesOnly option, ssh only offers the configured
IdentitiyFile. This option is useful for situations where the ssh agent
offers too many different identities causing an authentication failure.

mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,cockpit-project/cockpit