Fix for bug 926 - 500 Internal server error when sending a SOAP GetCapabilities request with invalid service parameter value.
Problem: Collection.max was executed on an empty list.

git-svn-id: https://svn.52north.org/svn/swe/main/SOS/Service/branches/52n-sos-400-refactored@20899 9b2695e2-e135-4693-8c03-170fd80ef316