Cinder: create target directory for targetcli-fb package
Cinder: create target directory for targetcli-fb package

While installing 'targetcli-fb' on bionic, a dependent package
'python-rtslib-fb' requires (but doesn't create) /etc/target
and fails[1] when this directory not found.
This patch creates the required directory.

[1] http://logs.openstack.org/26/641926/1/check/cinder-tempest-dsvm-lvm-lio-barbican/8f95df1/logs/devstacklog.txt.gz#_2019-03-13_03_36_44_623

Related-bug: #1819819
Change-Id: I7efefead873037da4aaacbdc6284458bdaad0f6b

dtroyer/devstack,nawawi/openstack,nawawi/openstack,dtroyer/devstack,openstack-dev/devstack,openstack-dev/devstack