revised health checker

milliseconds, almost instant ...

fix for earlier pr which failed on new installs
if disk was not present #848

quickemu

@@ -1770,6 +1770,15 @@ if [ -n "${VM}" ] && [ -e "${VM}" ]; then
         exit 1
     fi
 
+    if [ -e "${disk_img}" ]; then
+		DiskChkMsg="$("$QEMU_IMG" check -q "${disk_img}" 2>&1)"
+		if [[ $DiskChkMsg ]]; then
+		    echo; echo "ERROR! disk.qcow2 has problems. Try qemu-img check --help."
+		    echo; echo "$DiskChkMsg" ; echo
+		    exit 1
+		fi
+	fi
+
     VMDIR=$(dirname "${disk_img}")
     VMNAME=$(basename "${VM}" .conf)
     VMPATH=$(realpath "$(dirname "${VM}")")