Fix Behavior.PluginDefaults

It should check that the library falls back to LCB_IO_OPS_SELECT
without libevent

Change-Id: I932a7b69c6c05bc86f6e82add5c1b8ba28c4d01d
Reviewed-on: http://review.couchbase.org/28452
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>