Use -q option instead of > /dev/null redirect for ssh-add or don't hide any output

As you can see in the job log, output of ssh-add is not suppressed, > /dev/null doesn't help there.

$ echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add - > /dev/null
Identity added: (stdin) ((stdin))

I suggest to remove the redirection part and optionally add -q option, which, according to ssh-add manual, makes it quiet (and actually works). So the command should probably be changed to this:

$ echo "$SSH_PRIVATE_KEY" | tr -d '\r' | ssh-add -q -