[util] Make mtools check detect new versions

The mtools version check does not handle GNU mtools 4.0.10.  This commit
makes the pattern more general so it matches older mtools as well as the
newer "mtools (GNU mtools) 4.0.10" string.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

src/util/genliso

 esac
 
 case "`mtools -V`" in
-Mtools\ version\ 3.9.9*|Mtools\ version\ 3.9.1[0-9]*|Mtools\ version\ 4.*)
+Mtools\ version\ 3.9.9*|Mtools\ version\ 3.9.1[0-9]*|[mM]tools\ *\ [4-9].*)
 	;;
 *)
 	echo Mtools version 3.9.9 or later is required

src/util/gensdsk

 	;;
 esac
 case "`mtools -V`" in
-Mtools\ version\ 3.9.9*|Mtools\ version\ 3.9.1[0-9]*|Mtools\ version\ 4.*)
+Mtools\ version\ 3.9.9*|Mtools\ version\ 3.9.1[0-9]*|[mM]tools\ *\ [4-9].*)
 	;;
 *)
 	echo Mtools version 3.9.9 or later is required