clean.sh removes all the files

clean.sh was incorrectly looping over the list of files to remove. Because of
this the files were not being removed.

Change-Id: Ie0559e1d396a4d35df6a12dfbceefa7eb261bac5
Closes-Bug:1285924
diff --git a/clean.sh b/clean.sh
index e121e4f..3707d84 100755
--- a/clean.sh
+++ b/clean.sh
@@ -123,6 +123,6 @@
 FILES_TO_CLEAN=".localrc.auto docs-files docs/ shocco/ stack-screenrc test*.conf* test.ini*"
 FILES_TO_CLEAN+=".stackenv .prereqs"
 
-for file in FILES_TO_CLEAN; do
+for file in $FILES_TO_CLEAN; do
     rm -f $TOP_DIR/$file
 done