virsh: host: Use bitmap size in bytes rather than bit count

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1329819
(cherry picked from commit 3a703b81)

tools/virsh-host.c

@@ -699,7 +699,7 @@ cmdNodeCpuMap(vshControl *ctl, const vshCmd *cmd ATTRIBUTE_UNUSED)
 
     vshPrint(ctl, "%-15s ", _("CPU map:"));
     if (pretty) {
-        char *str = virBitmapDataToString(cpumap, cpunum);
+        char *str = virBitmapDataToString(cpumap, VIR_CPU_MAPLEN(cpunum));
 
         if (!str)
             goto cleanup;