Admin can now filter snapshots on the basis of tenant.
No changes are needed on server side since snapshot model contains
project_id as a column which means that it supports native filtering
by tenant (i.e, project) via SQL.
This closely follows similar functionality for volume listing added in
the change-id - fa8c7e3d84
DocImpact
After this patch is merged we need to regenerate the CLI reference
guide so that the added documentation for the new option
"--tenant <tenant_id>" for "cinder snapshot-list" command gets
included.
Change-Id: I0bbd8e0b4aaf25da738c67638fb497337ead312b
Co-Authored-By: wuyuting <wytdahu@gmail.com>