Merge pull request NixOS#364 from @basvandijk.

Also closes NixOS#361.

This makes sure that machines that are already deployed using the "none"
backend get the right public key before even attempting to connect
blindly.

To make sure this works even with new deployments, I successfully ran
the VM test for the "none" backend.

nixops/backends/none.py

@@ -29,6 +29,7 @@ def get_type(cls):
     target_host = nixops.util.attr_property("targetHost", None)
     _ssh_private_key = attr_property("none.sshPrivateKey", None)
     _ssh_public_key = attr_property("none.sshPublicKey", None)
+    _ssh_public_key_deployed = attr_property("none.sshPublicKeyDeployed", False, type = bool)
 
     def __init__(self, depl, name, id):
         MachineState.__init__(self, depl, name, id)
@@ -56,6 +57,12 @@ def create(self, defn, check, allow_reboot, allow_recreate):
             self.log_end("done.")
             self.vm_id = "nixops-{0}-{1}".format(self.depl.uuid, self.name)
 
+    def switch_to_configuration(self, method, sync, command=None):
+        res = super(NoneState, self).switch_to_configuration(method, sync, command)
+        if res == 0:
+            self._ssh_public_key_deployed = True
+        return res
+
     def get_ssh_name(self):
         assert self.target_host
         return self.target_host
@@ -68,7 +75,7 @@ def get_ssh_private_key_file(self):
 
     def get_ssh_flags(self):
         super_state_flags = super(NoneState, self).get_ssh_flags()
-        if self.vm_id and self.cur_toplevel:
+        if self.vm_id and self.cur_toplevel and self._ssh_public_key_deployed:
             return super_state_flags + ["-o", "StrictHostKeyChecking=no", "-i", self.get_ssh_private_key_file()]
         return super_state_flags