Dockerfile.rhel: fix a bash typo
Dockerfile.rhel: fix a bash typo

A regression was introduced in the Dockerfile, with a typo in
the condition:
https://github.com/openshift/origin/pull/26170

This patch fixes it.

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