pybind/mgr/rook: use AllMatcher when size is not provided

pybind/mgr/rook: use AllMatcher when size is not provided

Issue found by mypy 1.6.1. The previous code was:
`and ((sizematcher != None) or sizematcher.compare(device)`
meaning that if sizematcher is not none "return" true, but if
sizematcher is not none execute the compare method. This is of course
impossible as None will never have a compare method. I assume that the

At Kefu Chai's suggestion we can replace the None condition with an
AllMatcher object when no size is provided to create a size matcher.
This both corrects the error and makes the code much simpler and more
readable.

Signed-off-by: John Mulligan <jmulligan@redhat.com>