#1 Allow for creating rsa key on the remote host if it has none

[Krzysztof Kamil Jacewicz]

ssh-pull-id expects a remote hsot to have an existing rsa key to download and authorise locally.
If, however, the remote host does not have a key to download, there will be a message instructing the user to manually create the rsa key on the remote host, then re-run ssh-pull-id.
Instead, allow the ssh-pull-id to generate new passwordless rsa key on the remote host if none is present, and download it for authorizing.

For generating the passwordless key use this calling convention:
$ ssh-keygen -b 4096 -t rsa -f "$HOME/ssh/id_rsa" -q -N ""