HPCC-11522 libmemcached plugin

Previously: #6368 & #6686

Signed-off-by: jamienoss <james.noss@lexisnexis.com>
I'm not convinced by this.  I imagined it would report a warning N times, and then not report any more.  This will keep reporting warnings/errors but will still continue executing.  I think the else branch just needs to go.