Format timedelta microseconds using locale

issue11741
review412061003
(grafted from 1b1b11be474fbec7dfe1fb16e364e833661ce93f)

--HG--
branch : 6.0

tryton/common/timedelta.py

@@ -70,7 +70,7 @@ def format(value, converter=None):
         if not any(values[-3:]):
             # Add space if no time
             text += ' '
-        text += ('%.6f' % value)[1:]
+        text += locale.format_string('%.6f', value)[1:]
     return text