instance.cc: use new/delete for Hostlist
instance.cc: use new/delete for Hostlist

This is now a C++ object

Change-Id: I28ef55549cb3a94ac0636975aea578713b77438a
Reviewed-on: http://review.couchbase.org/69903
Reviewed-by: Sergey Avseyev <87f6d5e4fd3644c3c20800cde7fd3ad1569370b3@gmail.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

mody/libcouchbase,kojiromike/libcouchbase,kojiromike/libcouchbase,avsej/libcouchbase,avsej/libcouchbase,mody/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase,mody/libcouchbase,avsej/libcouchbase,avsej/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase,kojiromike/libcouchbase,avsej/libcouchbase,couchbase/libcouchbase,avsej/libcouchbase,couchbase/libcouchbase,avsej/libcouchbase,mody/libcouchbase,kojiromike/libcouchbase