fixes "exit status 255" issue with port forwarding

[hamir-suspect]

sometimes I had issues using sem port-forward command, it would just print out something like:

Forwarding 88.99.249.113:8800 -> 0.0.0.0:8800...
error: exit status 255

after some experimentation I got a bit better error from ssh Too many authentication failures adding -o IdentitiesOnly=yes resolves this issue