oidValidate() fails at OIDs containing a single 0 (ITS#3211)

[ando@sys-net.it]

Full_Name: Pierangelo Masarati
Version: HEAD (2.2?)
OS: Linux (irrelevant)
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (81.72.89.40)


The oidValidate() code is broken since it does not allow OIDs with a single '0',
e.g. "dc": "0.9.2342.19200300.100.1.25"; in fact, in OIDs portions starting with
a '0' should be illegal (e.g. "01.023"), but single '0's should be fine.