If the GSSAPI module is not present on the wallet server LDAP searches
will silently perform anonymous binds to the server.  This change means
that when GSSAPI is not present the wallet server will fail when LDAP
lookups are attempted.

diff --git a/perl/lib/Wallet/ACL/LDAP/Attribute.pm b/perl/lib/Wallet/ACL/LDAP/Attribute.pm
index 65e0208..02948e2 100644
--- a/perl/lib/Wallet/ACL/LDAP/Attribute.pm
+++ b/perl/lib/Wallet/ACL/LDAP/Attribute.pm
@@ -18,6 +18,7 @@ use strict;
 use warnings;
 
 use Authen::SASL;
+use GSSAPI;
 use Net::LDAP qw(LDAP_COMPARE_TRUE);
 use Wallet::ACL::Base;
 use Wallet::Config;