It is possible that the self._pwfunc() call returns a callable. For
instance, if the keyutils.osc.OscKernelKeyringBackend is configured
in the oscrc. Hence, check in credentials._LazyPassword.__str__
if the returned password is a callable and, if so, call it. Moreover,
a deprecation warning is printed. Eventually, this compat code will
be removed again.
This is a follow-up commit for commit
784d330f20 ("Only prompt for a password
if the server asks for it") (actually, it is a regression that was
not caught during the review...).
3262c05e35