set tv_usec to 0 rather than 1 when a fraction of a second is not

set tv_usec to 0 rather than 1 when a fraction of a second is not

        * glib/gtimer.c (g_time_val_from_iso8601): set tv_usec to 0 rather
        than 1 when a fraction of a second is not specified
        (g_time_val_from_iso8601): calculate a fraction of a second
        correctly even in case it does not happen to consist of exactly
        six digits; do not allow random data after the ISO 8601 string,
        only whitespace
        (make g_time_val_to_iso8601): support fractions of a second
        Patch by Peter Kjellerstedt

        * tests/testglib.c: Update to match

svn path=/trunk/; revision=7057