Bug #40697: Fix `xm list` parsing

For managed inactive domains `xm list` does not output a domain-ID and a state.

| # xm list
| Name                                        ID   Mem VCPUs      State   Time(s)
| Domain-0                                     0  3884     2     r-----     71.6
| yyy                                              512     1                 0.0
| xxx                                          7   512     1     -b----      1.1

Also cpu is not output.

Rewrite parseln() to use IFS for splitting and use number of output columns to
parse the lines.

--- a/debian/xen-utils-common.xendomains.init	2016-03-30 09:58:03.670755440 +0200
+++ b/debian/xen-utils-common.xendomains.init	2016-03-30 10:18:55.998019561 +0200
@@ -126,12 +126,16 @@
     done
 }
 
-parseln()
-{
-    name=`echo $1 | cut -d\  -f1`
-    name=${name%% *}
-    rest=`echo $1 | cut -d\  -f2-`
-    read id mem cpu vcpu state tm < <(echo "$rest")
+parseln () {
+	local IFS=' '
+	set -- $1  # IFS
+	case "$#" in
+	4) name=$1 id=   mem=$2 cpu=   vcpu=$3 state=   tm=$4 ;;
+	5) name=$1 id=   mem=$2 cpu=$3 vcpu=$4 state=   tm=$5 ;;
+	6) name=$1 id=$2 mem=$3 cpu=   vcpu=$4 state=$5 tm=$6 ;;
+	7) name=$1 id=$2 mem=$3 cpu=$4 vcpu=$5 state=$6 tm=$7 ;;
+	*) name= id= mem= cpu= vcpu= stat= tm= ; echo "Unknown 'xm list' output: $*" >&2 ;;
+	esac
 }
 
 is_running()
@@ -140,7 +144,7 @@
     RC=1
     while read LN; do
 	parseln "$LN"
-	if test $id = 0; then continue; fi
+	if [ -z "$id" ] || test $id = 0; then continue; fi
 	case $name in 
 	    ($NM)
 		RC=0
@@ -208,7 +212,7 @@
 {
     while read LN; do
 	parseln "$LN"
-	if test $id = 0; then continue; fi
+	if [ -z "$id" ] || test $id = 0; then continue; fi
 	if test "$state" != "-b---d" -a "$state" != "-----d"; then
 	    return 1;
 	fi
@@ -250,7 +254,7 @@
     echo -n "Shutting down Xen domains:"
     while read LN; do
 	parseln "$LN"
-	if test $id = 0; then continue; fi
+	if [ -z "$id" ] || test $id = 0; then continue; fi
 	echo -n " $name"
 	if test "$XENDOMAINS_AUTO_ONLY" = "true"; then
 	    case $name in
@@ -350,7 +354,7 @@
 {
     while read LN; do
 	parseln "$LN"
-	if test $id = 0; then continue; fi
+	if [ -z "$id" ] || test $id = 0; then continue; fi
 	case $name in 
 	    ($1)
 		return 0