Update the LDAP connection handler so that it only attempts to verify the key
manager provider and trust manager provider values if either SSL or StartTLS is
enabled.  Previously, if a key/trust manager provider value was provided, then
the server would require it to refer to a valid enabled key/trust manager
provider, even if it wouldn't be used.  Also, add a new check to ensure that if
SSL or StartTLS is enabled, then a valid key manager provider and trust manager
provider must have been configured for that connection handler.

OpenDS Issue Number:  1294