[server] Separate repository bootstrap from initialization Thus we now call 'bootstrap' here and there explicitly and remove call of this method in Repository.__init__(). This way instantiation of a Repository does not *implicitly* triggers the "bootstrap" step, which is arguably not a trivial thing and thus deserves to be independent. In __init__, set 'shutting_down' attribute to None and then to False in bootstrap as a mean to indicate that, when initialized, a repository is neither shutting down nor started (not sure where this is used though).

[server] Also remove tmpdir in case of error during restore database command

[server] Rename Repository's init_cnxset_pool method bootstrap See the (removed) docstring for a rationale...