Fixed type in get_audit_template_by_name method

Removed an extra underscore in the
get_audit_template_by__name method name in
watcher/db/api.py

Change-Id: I2687858ff4510c626c4dd2e2e9a5701405b5da55
Closes-Bug: #1548765

watcher/db/api.py

@@ -98,7 +98,7 @@ class BaseConnection(object):
         :raises: AuditTemplateNotFound
         """
 
-    def get_audit_template_by__name(self, context, audit_template_name):
+    def get_audit_template_by_name(self, context, audit_template_name):
         """Return an audit template.
 
         :param context: The security context