Fix typo in magnum/doc/source/dev/dev-manual-quickstart.rst
Fix typo in magnum/doc/source/dev/dev-manual-quickstart.rst

Change-Id: I6487a505f36bfa7074b52e4fd613b878fb82d54e

Tennyson53/magnum,ffantast/magnum,ramielrowe/magnum,eshijia/magnum,mjbrewer/testindex,openstack/magnum,ramielrowe/magnum,eshijia/SUR,sajuptpm/magnum,annegentle/magnum,Tennyson53/SUR,openstack/magnum,paulczar/magnum,sajuptpm/magnum,Alzon/SUR,hongbin/magnum,eshijia/magnum,hongbin/magnum,ArchiFleKs/magnum,mjbrewer/testindex,ChengTiesheng/magnum,ddepaoli3/magnum,ddepaoli3/magnum,ffantast/magnum,jay-lau/magnum,dimtruck/magnum,LaynePeng/magnum,eshijia/SUR,paulczar/magnum,LaynePeng/magnum,ArchiFleKs/magnum,dimtruck/magnum,mjbrewer/testindex,annegentle/magnum,Tennyson53/SUR,ChengTiesheng/magnum,Tennyson53/magnum,Alzon/SUR