manila share container name variable

manila share container name variable is fixed in some places,
but in the defaults directory, manila share container_name variable
is variable. If the manila share container_name variable is changed
during deployment, it will not be assigned to container name,
but a fixed 'manila_share' name.

Change-Id: Iea23c62518add8d6820b76b16edd3221906b0ffb