prepare: Always make sure primary output folders exist
prepare: Always make sure primary output folders exist

Gradle is aggressive about deleting bin folders when something changes.
Since it does this after the Bnd Projects are first prepared, we need
to ensure the output folders are recreated if necessary on future
calls to prepare.

Signed-off-by: BJ Hargrave <3d26bb3930946e3370762d769a073cece444c2d8@bjhargrave.com>

lostiniceland/bnd,mcculls/bnd,psoreide/bnd,magnet/bnd,psoreide/bnd,magnet/bnd,magnet/bnd,lostiniceland/bnd,lostiniceland/bnd,mcculls/bnd,mcculls/bnd,psoreide/bnd