kinect_fetch_fw: use curly braces when they are actually useful

diff --git a/kinect_fetch_fw b/kinect_fetch_fw
index 47f7b44..004fcc2 100755 (executable)
--- a/kinect_fetch_fw
+++ b/kinect_fetch_fw
@@ -59,14 +59,14 @@ echo -n "Extracting the UAC firmware..."
 echo " done."
 
 FW_FILE=$(ls UACFirmware.* | cut -d ' ' -f 1)
-FIRMWARE_PATH=$FW_DESTDIR/$(basename "$FW_FILE")
+FIRMWARE_PATH=${FW_DESTDIR}/$(basename "$FW_FILE")
 
 install -d "$FW_DESTDIR"
 install -m 644 "$FW_FILE" "$FIRMWARE_PATH"
 
 if [ -f "/lib/udev/rules.d/55-kinect_audio.rules" ];
 then
-  sed -e "s|@LOADER_PATH@|$LOADER_PATH|g" \
-      -e "s|@FIRMWARE_PATH@|$FIRMWARE_PATH|g" \
+  sed -e "s|@LOADER_PATH@|${LOADER_PATH}|g" \
+      -e "s|@FIRMWARE_PATH@|${FIRMWARE_PATH}|g" \
       -i "/lib/udev/rules.d/55-kinect_audio.rules"
 fi