Fix for DIRSTUDIO-899 (Unable to install Studio using the update site: "Missing requirement: ApacheDS Core 2.0.0.M11".
Removed useless apacheds-core dependency.

git-svn-id: https://svn.apache.org/repos/asf/directory/studio/trunk@1464957 13f79535-47bb-0310-9956-ffa450edef68