ldb: ldb_string_to_time reports more errors
The underlying function should return -1 and set errno when given invalid
strings, but we were not looking and have decided on 0 for error.
It would be a pain to change this function to return -1. Apart from the
API fuss, it is sometimes used unchecked to set an unsigned number and
an unchecked 0 is better than UINT*_MAX in those contexts.
It is probably not easy to get an -1 from a timegm() -- most
implementations will happily convert overflows for you, so e.g. the
15th month would be March of the next year. But EOVERFLOW is mentioned
in the manpages.
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>