Fix duplicate words RHOSP/RHV

Author: liangxia

installing/installing-preparing.adoc

@@ -20,8 +20,8 @@ If you want to install and manage {product-title} yourself, you can install it o
 * Microsoft Azure
 * Microsoft Azure Stack Hub
 * Google Cloud Platform (GCP)
-* {rh-openstack-first} ({rh-openstack})
-* {rh-virtualization-first} ({rh-virtualization})
+* {rh-openstack-first}
+* {rh-virtualization-first}
 * IBM Z and LinuxONE
 * IBM Z and LinuxONE for {op-system-base-full} KVM
 * IBM Power