fixes inconsistant chronological listing test

* Chronological order listing output for a same year, without entry
 timestamp (added metadata field), may vary

tests/test_usecase.py

@@ -519,25 +519,24 @@ class TestList(DataCommandTestCase):
     def test_list_chronological_order(self):
         cmds = ['pubs init',
                 'pubs import data/',
+                'pubs remove -f Einstein_1935',
+                'pubs remove -f Cesar2013',
                 'pubs list --chronological',
                 'pubs import bibexamples/noyear.bib',
                 'pubs list -C',
-
                 ]
-        data_chrono_correct = '[Einstein_1935] Einstein, A. et al. "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?" Physical Review (1935) \n' \
-                   '[Schrodinger_1935] Schrödinger, E. and Born, M. "Discussion of Probability Relations between Separated Systems" Mathematical Proceedings of the Cambridge Philosophical Society (1935) \n' \
+        data_chrono_correct = '[Schrodinger_1935] Schrödinger, E. and Born, M. "Discussion of Probability Relations between Separated Systems" Mathematical Proceedings of the Cambridge Philosophical Society (1935) \n' \
                    '[turing1950computing] Turing, Alan M "Computing machinery and intelligence" Mind (1950) \n' \
                    '[Bell_1964] Bell, J. S. "On the Einstein Podolsky Rosen paradox" Physics Physique физика (1964) \n' \
                    '[Page99] Page, Lawrence et al. "The PageRank Citation Ranking: Bringing Order to the Web." (1999) \n' \
                    '[10.1371_journal.pone.0038236] Saunders, Caroline Lyon AND Chrystopher L. Nehaniv AND Joe "Interactive Language Learning by Robots: The Transition from Babbling to Word Forms" PLoS ONE (2012) \n' \
-                   '[Cesar2013] César, Jean "An amazing title" Nice Journal (2013) \n' \
                    '[10.1371_journal.pone.0063400] Ay, Georg Martius AND Ralf Der AND Nihat "Information Driven Self-Organization of Complex Robotic Behaviors" PLoS ONE (2013) \n'
         correct = [ data_chrono_correct,
                    data_chrono_correct + '[Doe_noyear] Doe, John "About Assigning Timestamps to Research Articles" Journal Example \n'
                    ]
         outs = self.execute_cmds(cmds)
-        self.assertEqual(outs[2], correct[0])
-        self.assertEqual(outs[4], correct[1])
+        self.assertEqual(outs[4], correct[0])
+        self.assertEqual(outs[6], correct[1])
 
 class TestTag(DataCommandTestCase):