give back openldap on amd64

[Ryan Tandy <ryan@nardis.ca>]

Please retry openldap/2.5.12+dfsg-1 on amd64. The test suite still has a 
few flaky or timing-sensitive tests; this is probably one of them. It 
passed several times on my laptop, and on other arch buildds...

gb openldap_2.5.12+dfsg-1 . amd64

thank you,
Ryan