Fix Travis build error.

buku

@@ -299,7 +299,7 @@ class BukuDb:
         data_home = os.environ.get('XDG_DATA_HOME')
         if data_home is None:
             if os.environ.get('HOME') is None:
-                return '.'
+                return os.path.abspath('.')
             else:
                 data_home = os.path.join(os.environ.get('HOME'),
                                          '.local', 'share')

tests/test_bukuDb.py

@@ -66,7 +66,7 @@ class TestBukuDb(unittest.TestCase):
     def test_get_dbdir_path(self):
         dbdir_expected = TEST_TEMP_DBDIR_PATH
         dbdir_local_expected = join(expanduser('~'), '.local', 'share', 'buku')
-        dbdir_relative_expected = join('.', 'buku')
+        dbdir_relative_expected = os.path.abspath('.')
 
         # desktop linux
         self.assertEqual(dbdir_expected, BukuDb.get_dbdir_path())