Allow bitwise operations with subdoc flags
Allow bitwise operations with subdoc flags

This commit implements operator| for protocol_binary_subdoc_flag because
it's meant to be used as such.

Change-Id: I3d075bb873c454138a69ffeae95880844facf008
Reviewed-on: http://review.couchbase.org/66368
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

daverigby/kv_engine,daverigby/memcached,daverigby/kv_engine,couchbase/memcached,daverigby/memcached,couchbase/memcached,daverigby/kv_engine,daverigby/kv_engine,daverigby/memcached,couchbase/memcached,daverigby/memcached,couchbase/memcached