create -t aws-ec2 should probably make system wide ssh aware of that host/fingerprint

[yarikoptic]

ATM after we create aws-ec2 instance, if we decide to use it via datalad (e.g. within reproman run) it would use regular ssh (not reproman's login/paramiko) and then upon initial run ssh would inquire user to agree to that host to be safe to login. IMHO it should be done by reproman automagically (with some INFO level message) at the moment the instance is created

[yarikoptic]

extended idea: and not only of the fingerprint but also of the IP etc, so other tools (datalad) could easily login/use those resources. We could take an idea from git-annex in that for a new ssh remote it establishes, it adds to .ssh/config a new section like

# Added automatically by git-annex
Host git-annex-onerussian.com-yoh_.2Fhome.2Fyoh.2Fwww.2Fvideo.2Fford.2Dsayer.2D2014
    StrictHostKeyChecking yes
    Hostname onerussian.com
    Port 11110

So in our case for a resource named blah it could be

# Added automatically by ReproMan. Will be removed by "reproman delete"
Host blah.reproman
    StrictHostKeyChecking yes
    Hostname <IP>
    Port 22
    <Keys options>

which should also be removed by reproman delete, and then users could just ssh blah.reproman