Delete servers before deleting its share network

When deleting a share network, the belonging share servers were being
deleted automatically. However, any possible errors were being ignored,
possibly leaving share servers in the backend.

The patch https://review.openstack.org/644560 avoids this by making the
Manila API to return an error if the share network about to be deleted
still has any share server, which in turn has `is_auto_deletable=True`
or contains any share.

This patch modifies the base test class tearDown method, to delete the
share servers before the share network they belong to.

Change-Id: I7d330b8b5fb3f08d3cbdae2c1735e266e75a70d3
Depends-On: I4144a532d5827b929a1dce0d4d642e6d1cee47b1
Related-Bug: #1820118
3 files changed