ceph-volume: fix a bug in _check_generic_reject_reasons

ceph-volume: fix a bug in _check_generic_reject_reasons

The types of removable and ro are wrong. Here, both filters are not
working at all. Changed this from integer to string and corrected the test
data.

Delete redundant logic in get_block_devs_sysfs. Given the name of the
function, I think it is correct to judge from _check_generic_reject_reasons,
and in fact it was before v17.2.4.

Fixes: https://tracker.ceph.com/issues/58591
Signed-off-by: Kim Minjong <make.dirty.code@gmail.com>
(cherry picked from commit a78e660728c6c0442cdbfa65db776b5856aee933)