s3/loadparm.c: Change default value for "ldap ssl".

s3/loadparm.c: Change default value for "ldap ssl".

LDAP_SSL_ON is not defined at all. That's why the actual default value
was "" for a long time. Set a more sensible default value without chnging the
default behaviour.

-----8<------------------snip--------------8<--------------
user@host:/data/git/samba/v3-0-test/source> git grep LDAP_SSL_ON | cat
include/smb.h:enum ldap_ssl_types {LDAP_SSL_ON, LDAP_SSL_OFF,
LDAP_SSL_START_TLS};
param/loadparm.c:       Globals.ldap_ssl = LDAP_SSL_ON;
----->8------------------snap-------------->8--------------

It's the same in 3.2 and 3.3 series.

Karolin
(cherry picked from commit e6d883e003d4560c55259ae1cfdf7319602f76e3)