dsnap-sync: introduce support for automounter

- add parameter to set automounter-path
- handle start of systemd-unit on target

bin/dsnap-sync

@@ -627,6 +627,10 @@ parse_params () {
                 #  Call usage() function.
                 usage
                 ;;
+	    -a|--automount)
+		automount_path="$2"
+		shift 2
+		;;
             -b|--backupdir)
                 backupdir_cmdline="$2"
                 shift 2
@@ -729,6 +733,10 @@ parse_params () {
 		printf "%s v%s\n" "$progname" "$version"
 		exit 0
 		;;
+	    --automount=*)
+                automount_path=${1#*=}
+                shift
+                ;;
 	    --backupdir=*)
                 backupdir_cmdline=${1#*=}
                 shift
@@ -1613,6 +1621,7 @@ $progname $version
 Usage: $progname [options]
 
 Options:
+ -a, --automount <path>      start automount for given path to get a valid target mountpoint.
  -b, --backupdir <prefix>    backupdir is a relative path that will be appended to target backup-root
  -d, --description <desc>    Change the snapper description. Default: "latest incremental backup"
      --label-finished <desc> snapper description tagging successful jobs. Default: "dsnap-sync backup"