Wrap FWDIR in quotes in dev/check-license.

dev/check-license

@@ -51,7 +51,7 @@ acquire_rat_jar () {
 
 # Go to the Spark project root directory
 FWDIR="$(cd `dirname $0`/..; pwd)"
-cd $FWDIR
+cd "$FWDIR"
 
 if test -x "$JAVA_HOME/bin/java"; then
     declare java_cmd="$JAVA_HOME/bin/java"