openshift-tests: fix a --provider --dry-run edge case
openshift-tests: fix a --provider --dry-run edge case

Trying to override --provider while not actually connected to a
cluster (eg, to look at the output of --dry-run) would fail, rather
than just falling back to not trying to autodetect anything.

hroyrh/origin,jsafrane/origin,deads2k/origin,gabemontero/origin,soltysh/origin,akram/origin,deads2k/origin,gabemontero/origin,bparees/origin,JacobTanenbaum/origin,hroyrh/origin,sallyom/origin,bparees/origin,mahak/origin,xiuwang/origin,mfojtik/origin,xiuwang/origin,csrwng/origin,csrwng/origin,xiuwang/origin,openshift/origin,JacobTanenbaum/origin,jsafrane/origin,mahak/origin,coreydaley/origin,mfojtik/origin,coreydaley/origin,jsafrane/origin,bparees/origin,mfojtik/origin,sallyom/origin,csrwng/origin,openshift/origin,hroyrh/origin,coreydaley/origin,sallyom/origin,akram/origin,soltysh/origin,akram/origin,deads2k/origin,soltysh/origin,mahak/origin,JacobTanenbaum/origin,openshift/origin,gabemontero/origin