ldap: switch CA name to Equifax_Secure_CA

RapidSSL is only an intermediate certificate. The full chain is
RapidSSL -> GeoTrust Global -> Equifax. Set "ca_name" (i.e. what
check_cert checks) to Equifax.

Change-Id: I5cacf3ea289d19e671971f705cd796e1fb5f34cb
Merge "ldap: switch CA name to Equifax_Secure_CA" into production