v172 migration adds created_unix field instead of expiry (#15458)

The Session table must have an Expiry field not a created_unix field - somehow
this migration adds the incorrect named field leading to #15445 reports.

Fix #15445

Signed-off-by: Andrew Thornton <art27@cantab.net>

models/migrations/v172.go

@@ -14,7 +14,7 @@ func addSessionTable(x *xorm.Engine) error {
 	type Session struct {
 		Key    string `xorm:"pk CHAR(16)"`
 		Data   []byte `xorm:"BLOB"`
-		CreatedUnix timeutil.TimeStamp
+		Expiry timeutil.TimeStamp
 	}
 	return x.Sync2(new(Session))
 }