Update Linux flash script

Miwer commented in issue #11 that on Mint 17.3 lsblk does not escape
potentially unsafe characters like it does on Fedora (lsblk v2.32.1). So
broaden the grep match expression to catch both posibilities.

Flashing/flash_ts100_linux.sh

@@ -37,7 +37,7 @@ function enable_gautomount {
 }
 
 function is_attached {
-    output=`lsblk -b --raw --output NAME,MODEL | grep 'DFU\\\\x20Disk'`
+    output=`lsblk -b --raw --output NAME,MODEL | grep 'DFU.*Disk'`
     if [ $? -ne 0 ]; then
       return 1
     fi