create project REST service will fail on adding maintainer

- we flush early and that causes an update when adding the user as maintainer, which then failed on update permission check because he is not yet a maintainer

zanata-war/src/main/java/org/zanata/rest/service/ProjectService.java

@@ -169,19 +169,16 @@ else if (Objects.equal(hProject.getStatus(), READONLY)) {
 
         transfer(project, hProject);
 
-        hProject = projectDAO.makePersistent(hProject);
-        projectDAO.flush();
-
         if (identity != null && hProject.getMaintainers().isEmpty()) {
             HAccount hAccount =
                     accountDAO.getByUsername(identity.getCredentials()
                             .getUsername());
             if (hAccount != null && hAccount.getPerson() != null) {
                 hProject.getMaintainers().add(hAccount.getPerson());
             }
-            projectDAO.flush();
         }
 
+        projectDAO.makePersistent(hProject);
         etag = eTagUtils.generateTagForProject(projectSlug);
         return response.tag(etag).build();