Add missing wipeVolume to MachineConfig luks sections

We're reusing the existing root partition, so Ignition will fail without
this.

The RCCs in installation-special-config-mirrored-disk.adoc don't need this
because boot_device.luks automatically adds wipeVolume when desugared.

Author: bgilbert

modules/installation-special-config-encrypt-disk-tang.adoc

@@ -99,6 +99,7 @@ spec:
               - url: https://tang.example.com
                 thumbprint: PLjNyRdGw03zlRoGjQYMahSZGu9
           options: [--cipher, aes-cbc-essiv:sha256]
+          wipeVolume: true
       filesystems:
         - device: /dev/mapper/root
           format: xfs
@@ -131,6 +132,7 @@ spec:
               - url: https://tang.example.com
                 thumbprint: PLjNyRdGw03zlRoGjQYMahSZGu9
           options: [--cipher, aes-cbc-essiv:sha256]
+          wipeVolume: true
       filesystems:
         - device: /dev/mapper/root
           format: xfs

modules/installation-special-config-encrypt-disk-tpm2.adoc

@@ -52,6 +52,7 @@ spec:
           clevis:
             tpm2: true
           options: [--cipher, aes-cbc-essiv:sha256]
+          wipeVolume: true
       filesystems:
         - device: /dev/mapper/root
           format: xfs
@@ -81,6 +82,7 @@ spec:
           clevis:
             tpm2: true
           options: [--cipher, aes-cbc-essiv:sha256]
+          wipeVolume: true
       filesystems:
         - device: /dev/mapper/root
           format: xfs