Description of problem:

When installing a guest on Power using virt-install with a "serial" console (actually the paravirtualized hypervisor console), virt-install gives this warning:

    WARNING  No 'console' seen in --extra-args, a 'console=ttyS0'
    kernel argument is likely required to see text install output
    from the guest.

This warning is incorrect on two counts: 1) the console= argument is not actually necessary because the Power kernel/userspace automatically use the hypervisor console as well a a graphical console if present,  2) to explicitly select the hypervisor console, the correct argument is console=hvc0, not console=ttyS0 (since it's not actually a serial console).

Basically, for Power systems, having only the hypervisor console, but not VGA console is the normal, rather than the exceptional case.

Version-Release number of selected component (if applicable):

virt-install-1.2.1-3.el7.noarch
virt-manager-common-1.2.1-3.el7.noarch
libvirt-daemon-kvm-1.2.17-2.el7.ppc64le

How reproducible:

100%

Steps to Reproduce:

1. virt-install \
      --name test \
      --location http://download.lab.bos.redhat.com/.../os/ \
      --ram=2048 \
      --vcpus=1 \
      --accelerate \
      --os-variant=rhel7.0 \
      --graphics none \
      --network network=default,model=virtio \
      --disk size=10,bus=scsi

Actual results:

Installer prints the warning described above before continuing successfully with installation.

Expected results:

Installation runs without warning.