qvm-copy-to-vm2.kde: prepare for a race in PROGRESS_FILE creation

Apparently a tight race may happen when PROGRESS_FILE has been created,
but not yet written to by qfile-agent. Check if its content are
sane before use.

appvm/qvm-copy-to-vm2.kde

@@ -34,6 +34,7 @@ while ! [ -s $PROGRESS_FILE ] ; do
 done
 while true ; do
 	read agentpid sentsize agentstatus < $PROGRESS_FILE
+	if [ "x"$agentstatus = x ] ; then continue ; fi
 	if ! [ -e /proc/$agentpid ] ; then break ; fi
 	if [ "x"$agentstatus = xdone ] ; then break ; fi
 	CURRSIZE=$(($sentsize/1024))