FS-11614: [Packaging] Use full path for the chown command in the systemd unit.

debian/freeswitch-systemd.freeswitch.service

@@ -12,7 +12,7 @@ Type=forking
 PIDFile=/run/freeswitch/freeswitch.pid
 Environment="DAEMON_OPTS=-nonat"
 EnvironmentFile=-/etc/default/freeswitch
-ExecStartPre=chown -R freeswitch:freeswitch /var/lib/freeswitch /var/log/freeswitch /etc/freeswitch /usr/share/freeswitch /var/run/freeswitch
+ExecStartPre=/bin/chown -R freeswitch:freeswitch /var/lib/freeswitch /var/log/freeswitch /etc/freeswitch /usr/share/freeswitch /var/run/freeswitch
 ExecStart=/usr/bin/freeswitch -u freeswitch -g freeswitch -ncwait $DAEMON_OPTS
 TimeoutSec=45s
 Restart=always