Fix for deleting audit template

We need to update sqlalchemy/api and sqlalchemy/models (and appropriate tests)
to support deleting audit templates and recreating them with the same names.

Change-Id: Icf54cf1ed989a3f2ad689e25be4474b16a3a3eb2
Related-Bug: #1510179

watcher/db/sqlalchemy/models.py

@@ -116,7 +116,6 @@ class AuditTemplate(Base):
     __tablename__ = 'audit_templates'
     __table_args__ = (
         schema.UniqueConstraint('uuid', name='uniq_audit_templates0uuid'),
-        schema.UniqueConstraint('name', name='uniq_audit_templates0name'),
         table_args()
     )
     id = Column(Integer, primary_key=True)