Only set default filesystem to XFS in CentOS

Fedora default filesystem is a messier situation.  This makes
it easier to inherit Fedora builds.

Signed-off-by: Colin Walters <walters@verbum.org>

tier-0/bootc-config.yaml

@@ -1,10 +0,0 @@
-# Configuration for bootc
-postprocess:
-  # XFS is our default filesystem
-  - |
-    #!/usr/bin/env bash
-    mkdir -p /usr/lib/bootc/install/
-    cat > /usr/lib/bootc/install/20-rhel.toml << EOF
-    [install]
-    root-fs-type = "xfs"
-    EOF

tier-0/manifest.yaml

@@ -51,7 +51,6 @@ remove-from-packages:
 include:
   - bootc.yaml
   - ostree.yaml
-  - bootc-config.yaml
   - initramfs.yaml
   - autoupdates.yaml
   - basic-fixes.yaml