permission: generate team avatar url with default

pkg/api/dashboard_permission.go

@@ -30,7 +30,10 @@ func GetDashboardPermissionList(c *m.ReqContext) Response {
 
 	for _, perm := range acl {
 		perm.UserAvatarUrl = dtos.GetGravatarUrl(perm.UserEmail)
-		perm.TeamAvatarUrl = dtos.GetGravatarUrl(perm.TeamEmail)
+
+		if perm.TeamId > 0 {
+			perm.TeamAvatarUrl = dtos.GetGravatarUrlWithDefault(perm.TeamEmail, perm.Team)
+		}
 		if perm.Slug != "" {
 			perm.Url = m.GetDashboardFolderUrl(perm.IsFolder, perm.Uid, perm.Slug)
 		}