This function takes the following parameters:
The DN of the entry subject of scope test.
The base DN to which dn is going to be tested against.
The scope tested. This parameter can take one of the following levels
LDAP_SCOPE_BASE - where the entry DN should be the same as the base DN
LDAP_SCOPE_ONELEVEL - where the base DN should be the parent of the entry DN
LDAP_SCOPE_SUBTREE - where the base DN should at least be the suffix of the entry DN