Flag image_fail_and_sync_test_2 as developer

 - Intermittent failure on Travis-CI when run repeatedly
   `ctest --output-on-failure --repeat-until-fail 10`
 - Bug report: #390

Author: zbeekman

CMakeLists.txt

@@ -559,7 +559,9 @@ if(opencoarrays_aware_compiler)
       set_property(TEST image_fail_test_1 PROPERTY FAIL_REGULAR_EXPRESSION "Test failed")
       set_property(TEST image_fail_test_1 PROPERTY PASS_REGULAR_EXPRESSION "Test passed")
       add_fault_tolerant_mpi_test(image_fail_and_sync_test_1 4 ${tests_root}/unit/fail_images/image_fail_and_sync_test_1)
-      add_fault_tolerant_mpi_test(image_fail_and_sync_test_2 4 ${tests_root}/unit/fail_images/image_fail_and_sync_test_2)
+      if (CAF_RUN_DEVELOPER_TESTS OR $ENV{OPENCOARRAYS_DEVELOPER})
+        add_fault_tolerant_mpi_test(image_fail_and_sync_test_2 4 ${tests_root}/unit/fail_images/image_fail_and_sync_test_2)
+      endif()
       add_fault_tolerant_mpi_test(image_fail_and_sync_test_3 4 ${tests_root}/unit/fail_images/image_fail_and_sync_test_3)
       add_fault_tolerant_mpi_test(image_fail_and_status_test_1 4 ${tests_root}/unit/fail_images/image_fail_and_status_test_1)
       add_fault_tolerant_mpi_test(image_fail_and_failed_images_test_1 4 ${tests_root}/unit/fail_images/image_fail_and_failed_images_test_1)