When we reach xtremio_volumes_per_glance_cache, it is not able
to create more clones for the image-volume therefore requires to
create a new cache entry.
Keeping in mind the case in [1], we can get CinderException for
various reasons from different drivers during the clone operation.
So we define a new exception for the xtremio driver to force create
a new cache entry when the limit reaches and not enforce the same
for other drivers.
[1] https://bugs.launchpad.net/cinder/+bug/1552734
Conflicts:
cinder/exception.py
cinder/tests/unit/volume/flows/test_create_volume_flow.py
Closes-Bug: #1858169
Change-Id: I2bf964d5a7b2048db9be1ea3eb97cd517e112c5b
(cherry picked from commit d22e54c254)
e3c9fa4efa