Use regular expression instead of split when replacing authorized_keys
Use regular expression instead of split when replacing authorized_keys

In some cases (e.g. Ubuntu cloud-init) authorized_keys may contain quoted spaces as part of options:
`no-port-forwarding,no-agent-forwarding,no-X11-forwarding,com‌​mand="echo 'Please login as the user \"ubuntu\" rather than the user \"root\".';echo;sleep 10" ssh-rsa xxxxxx`
which confused the split in _replace_auth_key() in modules/ssh.py.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt