srm: Property name refinements

Renamed srm.enable.client.dns.lookup to srm.enable.client-dns-lookup.

Marked srmIgnoreClientProtocolOrder as obsolete. The same functionality
can be achieved setting srm.protocols.preferred to an empty or non-empty
list.

Target: trunk
Require-book: yes
Require-notes: yes
Acked-by: Dmitry Litvintsev <litvinse@fnal.gov>
Patch: http://rb.dcache.org/r/5863/