Fixed mail for check disk space

roles/common/templates/etc/cron.hourly/check-disk-space.sh.j2

@@ -3,7 +3,7 @@
 # Check disk space
 CURRENT=$(df / --output=pcent | tail --lines=1 | cut --delimiter='%' --field=1)
 THRESHOLD=90
-ADMIN="root@{{ ansible_domain }}"
+ADMIN="{{ admin_mail }}"
 SUBJECT="[Disk Space Alert] The free space on {{ ansible_fqdn }} is critically low"
 MESSAGE=
 
@@ -12,4 +12,3 @@ if [ "$CURRENT" -gt "$THRESHOLD" ]; then
 Your root partition remaining free space is critically low. Used: $CURRENT%
 EOF
 fi
-