Adding patch to mbed-ls test for reliability

Author: bridadan

legacy/mbed-ls/test/platform_database.py

@@ -70,7 +70,9 @@ def test_broken_database_bad_json(self):
     def test_broken_database(self):
         """Verify that the platform database correctly reset's its database
         """
-        with patch("mbed_os_tools.detect.platform_database.open") as _open:
+        with patch("mbed_os_tools.detect.platform_database.open") as _open,\
+             patch("mbed_os_tools.detect.platform_database._older_than_me") as _older:
+            _older.return_value = False
             stringio = MagicMock()
             _open.side_effect = (IOError("Bogus"), stringio)
             self.pdb = PlatformDatabase([LOCAL_PLATFORM_DATABASE])