fix: do not quote nuke arg

Quoting the nuke arg when nuke was missing resulted in an empty
trailing argument passed to roundup-demo that was interpreted as
a position argument to set the database type.

$nuke is exactly the word nuke so no need to quote it as though it
could contain multiple space separated tokens.

Author: rouilj

scripts/Docker/roundup_start

@@ -129,7 +129,7 @@ for tracker_spec in "$@"; do
 			 --urlport "$PORT_8080" \
 			 -t "$template" \
 			 tracker/demo \
-			 "$nuke"
+			 $nuke
 		fi
 		;;
 	    shell)