glfs: set WCE
glfs: set WCE

glfs will want to report WCE enabled, so it can use
the SYNCHRONIZE CACHE/flush to make sure data is written
from device caches to their medium.

See PR 159:
https://github.com/open-iscsi/tcmu-runner/pull/159

Signed-off-by: Mike Christie <39daeb1549a929782e38aa87c4e3da7f3844b09a@redhat.com>

agrover/tcmu-runner,open-iscsi/tcmu-runner,open-iscsi/tcmu-runner