PLT-2905 fixing upgrade of SSO accounts (#2962)

* PLT-2905 fixing upgrade of SSO accounts

* Fixing multiple Auths mapped to different emails

model/gitlab/gitlab.go

@@ -47,7 +47,7 @@ func userFromGitLabUser(glu *GitLabUser) *model.User {
 	}
 	strings.TrimSpace(user.Email)
 	user.Email = glu.Email
-	user.AuthData = strconv.FormatInt(glu.Id, 10)
+	*user.AuthData = strconv.FormatInt(glu.Id, 10)
 	user.AuthService = model.USER_AUTH_SERVICE_GITLAB
 
 	return user