README: Fix broken links to openstack and vmware
README: Fix broken links to openstack and vmware

Update links to openstack and vmware terraform install docs, and make them reference format, too.

Ref: https://coreos.slack.com/archives/C2ZA5QGMV/p1509456941000394
colemickens/tectonic-installer,lander2k2/tectonic-installer,alexsomesan/tectonic-installer,alexsomesan/tectonic-installer,mrwacky42/tectonic-installer,justaugustus/tectonic-installer,hhoover/tectonic-installer,zbwright/tectonic-installer,colemickens/tectonic-installer,aknuds1/tectonic-installer,aknuds1/tectonic-installer,hhoover/tectonic-installer,cpanato/tectonic-installer,coreos/tectonic-installer,kalmog/tectonic-installer,aknuds1/tectonic-installer,coreos/tectonic-installer,lander2k2/tectonic-installer,lander2k2/tectonic-installer,derekhiggins/installer,lander2k2/tectonic-installer,rithujohn191/tectonic-installer,zbwright/tectonic-installer,metral/tectonic-installer,hhoover/tectonic-installer,rithujohn191/tectonic-installer,colemickens/tectonic-installer,justaugustus/tectonic-installer,squat/tectonic-installer,mrwacky42/tectonic-installer,metral/tectonic-installer,colemickens/tectonic-installer,mrwacky42/tectonic-installer,kyoto/tectonic-installer,metral/tectonic-installer,alexsomesan/tectonic-installer,squat/tectonic-installer,s-urbaniak/tectonic-installer,joshix/tectonic-installer,mrwacky42/tectonic-installer,squat/tectonic-installer,kyoto/tectonic-installer,s-urbaniak/tectonic-installer,cpanato/tectonic-installer,joshix/tectonic-installer,coreos/tectonic-installer,zbwright/tectonic-installer,kalmog/tectonic-installer,zbwright/tectonic-installer,hhoover/tectonic-installer,kyoto/tectonic-installer,derekhiggins/installer,coreos/tectonic-installer,squat/tectonic-installer,metral/tectonic-installer,kyoto/tectonic-installer,rithujohn191/tectonic-installer,kalmog/tectonic-installer,mrwacky42/tectonic-installer,joshix/tectonic-installer,aknuds1/tectonic-installer,s-urbaniak/tectonic-installer,metral/tectonic-installer,aknuds1/tectonic-installer,s-urbaniak/tectonic-installer,cpanato/tectonic-installer,justaugustus/tectonic-installer,hhoover/tectonic-installer,alexsomesan/tectonic-installer,rithujohn191/tectonic-installer,alexsomesan/tectonic-installer,coreos/tectonic-installer,zbwright/tectonic-installer,s-urbaniak/tectonic-installer,colemickens/tectonic-installer,justaugustus/tectonic-installer,kyoto/tectonic-installer,justaugustus/tectonic-installer,rithujohn191/tectonic-installer,joshix/tectonic-installer,joshix/tectonic-installer,cpanato/tectonic-installer