UObject Fix yield_* functions.
UObject Fix yield_* functions.

The code was wrong, but the recent change in utime() backend triggered the bug.

	* src/liburbi/usyncclient.cc (processEvent): Perform at least
	one check no matter what the timeout says.

urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi