Remove XFS filesystem from the daily mlocate cron job

This fix removes the XFS filesystem from the daily cron job.
It will help to remove unnecessary disk IO due to updatedb/mlocate
swift object indexing inside the /srv/node folders.

Change-Id: I8bfa92003ce06ee4f065663e054cd2d04f458ec6
Closes-Bug: #1572307

releasenotes/notes/swift-reconfigure-xfs-from-mlocate-e4844e6c0469afd6.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - The XFS filesystem is excluded from the daily mlocate crond job
+    in order to conserve disk IO for large IOPS bursts due to
+    updatedb/mlocate file indexing.

tasks/swift_pre_install.yml

@@ -109,3 +109,13 @@
   tags:
     - swift-dirs
     - swift-logs
+
+- name: Configure mlocate for cron.daily
+  template:
+    src: "mlocate-crond-daily.sh.j2"
+    dest: "/etc/cron.daily/mlocate"
+    mode: "0755"
+    owner: "root"
+    group: "root"
+  tags:
+    - swift-crond

templates/mlocate-crond-daily.sh.j2

@@ -0,0 +1,21 @@
+#! /bin/bash
+# {{ ansible_managed }}
+
+set -e
+
+[ -x /usr/bin/updatedb.mlocate ] || exit 0
+
+if which on_ac_power >/dev/null 2>&1; then
+    ON_BATTERY=0
+    on_ac_power >/dev/null 2>&1 || ON_BATTERY=$?
+    if [ "$ON_BATTERY" -eq 1 ]; then
+        exit 0
+    fi
+fi
+
+# See ionice(1)
+if [ -x /usr/bin/ionice ] && /usr/bin/ionice -c3 true 2>/dev/null; then
+    IONICE="/usr/bin/ionice -c3"
+fi
+
+flock --nonblock /run/mlocate.daily.lock $IONICE /usr/bin/updatedb.mlocate --prunefs xfs