[GEODE-5545] Modify instance creation.
[GEODE-5545] Modify instance creation.

* Explicitly state what network and subnet to launch the instance in.

Signed-off-by: Finn Southerland <5cdc37c4d4124ae68c3c3e518960e1cf8f0ddc52@pivotal.io>

smgoller/geode,jdeppe-pivotal/geode,davebarnes97/geode,smgoller/geode,deepakddixit/incubator-geode,davebarnes97/geode,masaki-yamakawa/geode,PurelyApplied/geode,davebarnes97/geode,deepakddixit/incubator-geode,jdeppe-pivotal/geode,davebarnes97/geode,masaki-yamakawa/geode,pdxrunner/geode,jdeppe-pivotal/geode,davinash/geode,smgoller/geode,smgoller/geode,deepakddixit/incubator-geode,davinash/geode,PurelyApplied/geode,deepakddixit/incubator-geode,deepakddixit/incubator-geode,smgoller/geode,PurelyApplied/geode,davinash/geode,PurelyApplied/geode,masaki-yamakawa/geode,masaki-yamakawa/geode,PurelyApplied/geode,pdxrunner/geode,davinash/geode,masaki-yamakawa/geode,pdxrunner/geode,davebarnes97/geode,jdeppe-pivotal/geode,PurelyApplied/geode,smgoller/geode,PurelyApplied/geode,masaki-yamakawa/geode,jdeppe-pivotal/geode,davinash/geode,jdeppe-pivotal/geode,smgoller/geode,jdeppe-pivotal/geode,davinash/geode,pdxrunner/geode,pdxrunner/geode,davebarnes97/geode,pdxrunner/geode,davebarnes97/geode,deepakddixit/incubator-geode,davinash/geode,pdxrunner/geode,deepakddixit/incubator-geode,masaki-yamakawa/geode