Fix for pgbackrest systemd service file

Good afternoon,

I was talking with David Steele and pointed out errors I saw in the
pgbackrest service file when doing some early TLS file. It looks like the
errors stem from line 15 where the kill command doesn't have the absolute
path, and should be /bin/kill. I confirmed the errors go away when I
specify the full path to the kill binary.

I've given David this info and he is updating their documentation to
reflect the change also.

Before:

$ sudo systemctl status pgbackrest
● pgbackrest.service - pgBackRest Server
Loaded: loaded (/lib/systemd/system/pgbackrest.service; disabled; vendor
preset: enabled)
Active: inactive (dead)

Jul 19 16:37:44 postgres-history0-az-eastus2 systemd[1]:
/lib/systemd/system/pgbackrest.service:15: Executable path is not absolute:
kill -HUP $MAINPID

After:

$ sudo systemctl status pgbackrest
● pgbackrest.service - pgBackRest Server
Loaded: loaded (/lib/systemd/system/pgbackrest.service; disabled; vendor
preset: enabled)
Active: inactive (dead)

Diff on an Ubuntu 18.04 system:

$ sudo diff -u pgbackrest.service.old /lib/systemd/system/pgbackrest.service
--- pgbackrest.service.old 2022-07-26 17:19:37.321260963 +0000
+++ /lib/systemd/system/pgbackrest.service 2022-07-26
15:34:51.100155390 +0000
@@ -12,7 +12,7 @@
ExecStart=/usr/bin/pgbackrest server
ExecStartPost=/bin/sleep 3
ExecStartPost=/bin/bash -c "[ ! -z $MAINPID ]"
-ExecReload=kill -HUP $MAINPID
+ExecReload=/bin/kill -HUP $MAINPID

[Install]
WantedBy=multi-user.target
--
Don Seiler
www.seiler.us