Don't discard the value of DISABLE_REGULAR_ORG_CREATION (#5886)

* Consider the configuration value of DISABLE_REGULAR_ORG_CREATION when
creating a user

models/user.go

@@ -814,6 +814,7 @@ func CreateUser(u *User) (err error) {
 	u.AllowCreateOrganization = setting.Service.DefaultAllowCreateOrganization
 	u.MaxRepoCreation = -1
 	u.Theme = setting.UI.DefaultTheme
+	u.AllowCreateOrganization = !setting.Admin.DisableRegularOrgCreation
 
 	if _, err = sess.Insert(u); err != nil {
 		return err