Latest versions of OS comes with fuse3 installed and we are checking for
only fuse in the get_package_version check in the test case. Checking just
for the package string fuse will return None if only fuse3 is installed.
Adding check for both fuse and fuse3 packages now and also handling NoneType
return in _is_flockable() if the package is actually missing.
Fixes: https://tracker.ceph.com/issues/75959 Signed-off-by: Karthik U S <karthik.u.s1@ibm.com>