Fix Swift with kernel 4.19 and later

We mount Swift volumes with xfs.
The 'nobarrier' option we used was made noop [1]
and deprecated [2] (with warning) in kernel 4.10.
In 4.19 it was removed [3] resulting in an error
when using e.g. Debian Buster as host.
The noop patch was backported to CentOS 7 so
it is safe to remove this option with no behavior
change and backport to where needed.
Ubuntu Bionic uses 4.15 which only warns.
CentOS 8 uses 4.18 which only warns as well.
Debian Buster uses 4.19 exactly which breaks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2291dab2c9d1880efd19469df2042e2277c8b7a4
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4cf4573d899cd80d8578c050061dc342f99f3a32
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1c02d502c20809a2a5f71ec16a930a61ed779b81

Change-Id: I006dea21321146c7fc738d0b41c401b72d271a99
Closes-bug: #1800132

ansible/roles/swift/tasks/start.yml

@@ -25,7 +25,7 @@
   mount:
     src: "UUID={{ item.fs_uuid }}"
     fstype: xfs
-    opts: "noatime,nodiratime,nobarrier,logbufs=8"
+    opts: "noatime,nodiratime,logbufs=8"
     state: mounted
     name: "{{ swift_devices_mount_point }}/{{ item['fs_label'] }}"
   with_items: "{{ swift_disks }}"

releasenotes/notes/fix-swift-mount-xfs-nobarrier-44a1601da46d12b9.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixes Swift volume mounting failing on kernel 4.19 and later due to
+    removal of `nobarrier` from XFS mount options.
+    See `bug 1800132 <https://bugs.launchpad.net/kolla-ansible/+bug/1800132>`__
+    for details.