[py3] Let InstanceCommand.run_arg() always return an int
The caller of this method (which is method "run_args") does `max(status,
self.run_arg(appid))` and run_arg might return None if the underlying
<cmdname>_instance method returns None. On python3 max(1, None) breaks
with "TypeError: unorderable types: int() > NoneType()". So we enforce
run_arg() method to return an integer even if the underlying method
returns None.
This fixes call of "cubicweb-ctl i18ninstance" with Python3.
[MASTER]
load-plugins=cubicweb.pylintext
ignore=__pkginfo__
[MESSAGES CONTROL]
disable = too-many-ancestors,too-many-instance-attributes,too-many-public-methods,
too-few-public-methods,too-many-arguments,import-error
[BASIC]
function-rgx = [a-z_][a-z0-9_]{2,35}$
good-names=w,_
[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception
[CLASSES]
exclude-protected=_cw,_cnx,
# namedtuple public API.
_asdict,_fields,_replace,_source,_make
[FORMAT]
max-line-length=100
max-module-lines=2000