backups: give is a low oomScoreAdjust to not get killed

src/scripts/starttask.sh

@@ -24,6 +24,7 @@ readonly task_id="$1"
 readonly logfile="$2"
 readonly nice="$3"
 readonly memory_limit_mb="$4" # SI units
+readonly oom_score_adjust="$5"
 
 readonly service_name="box-task-${task_id}"
 systemctl reset-failed "${service_name}" 2>/dev/null || true
@@ -31,7 +32,7 @@ systemctl reset-failed "${service_name}" 2>/dev/null || true
 readonly id=$(id -u $SUDO_USER)
 readonly ubuntu_version=$(lsb_release -rs)
 
-options="-p TimeoutStopSec=10s -p MemoryMax=${memory_limit_mb}M --pipe --wait"
+options="-p TimeoutStopSec=10s -p MemoryMax=${memory_limit_mb}M -p OOMScoreAdjust=${oom_score_adjust} --pipe --wait"
 
 # Note: BindsTo will kill this task when the box is stopped. but will not kill this task when restarted!
 # For this reason, we have code to kill the tasks both on shutdown and startup.