Fix field type to audit_type

There's a number of places where a field of an object is named "type",
which isn't good thing. Actually type is keyword in python, so wherever
I found type used in models/api/object/test, I have fixed it to
audit_type in the audit files

Change-Id: Iea6bd3acb0b2af2a833b3916701aad88f6064bba
Closes-Bug: #1533392

watcher/db/sqlalchemy/models.py

@@ -171,7 +171,7 @@ class Audit(Base):
     )
     id = Column(Integer, primary_key=True)
     uuid = Column(String(36))
-    type = Column(String(20))
+    audit_type = Column(String(20))
     state = Column(String(20), nullable=True)
     deadline = Column(DateTime, nullable=True)
     audit_template_id = Column(Integer, ForeignKey('audit_templates.id'),