External poller, dual auth improvements

[jweede]

Made some improvements to our instance, would like to contribute back and solicit feedback. Thanks in advance.

• Added an "external poller command": This lets us populate ApacheDS via script immediately after the initial sync. We augment the ApacheDS directory with ssh keys and info from other sources. It's kind of a hack, but works well for us
• Dual Validator auth order: changed the auth order to attempt secret key auth first if the password looks like a secret key. This cuts down on the amount of errant logins in our CloudWatch logs.
• ant build.xml fix: On latest master I hit an error with the build.xml ("A zip file cannot include itself"), but the following change fixed it.