Remove use of $OPTIND in dcos-install.sh
Remove use of $OPTIND in dcos-install.sh

Fixes: DCOS_OSS-2438

dcos/dcos,GoelDeepak/dcos,mesosphere-mergebot/dcos,mesosphere-mergebot/mergebot-test-dcos,dcos/dcos,GoelDeepak/dcos,mesosphere-mergebot/mergebot-test-dcos,kensipe/dcos,mesosphere-mergebot/dcos,dcos/dcos,GoelDeepak/dcos,mesosphere-mergebot/mergebot-test-dcos,mesosphere-mergebot/mergebot-test-dcos,kensipe/dcos,kensipe/dcos,dcos/dcos,dcos/dcos,mesosphere-mergebot/dcos,kensipe/dcos,GoelDeepak/dcos,mesosphere-mergebot/dcos