The real engines config should not start with the separator
The real engines config should not start with the separator

When parsing the config string provided by the client ewb
engine did not swallow the separator character resulting
in passing the string:

    ;keep_deleted=true

to the engine

Change-Id: Ic38534d67c2e10efbb2e611580350bc566f3d009
Reviewed-on: http://review.couchbase.org/70856
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

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