(ITS#7048) Non root binding causes assert

[aitor.carrera@edosoftfactory.com]

Full_Name: Aitor Carrera
Version: 2.4.21
OS: SLES10
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (95.126.219.248)


When we use a non root user to bind, with multiple threads and some concurrent
proxies

1 .- In meta_back_bind_op_result method, in back-meta bind.c file the assert
"assert( LDAP_BACK_CONN_BINDING( msc ) );" is evaluated to false.
  
2.- Next, calls meta_back_cancel (bind.c) and then  ldap_abandon_ext and other
assert is evaluated to false:

slapd: sasl.c:74: ldap_sasl_bind: Assertion `ld != ((void *)0)' failed.

That crash the slapd.