paycheck: improved test script error message

Makes it clear what exactly is not found (i.e. the paycheck.py at the
same location as test_paycheck.sh).

BUG=None
TEST=Error message as expected

Change-Id: I240c75ecb38c1003882aff76a65f92b661f8a607
Reviewed-on: https://gerrit.chromium.org/gerrit/51011
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/scripts/test_paycheck.sh b/scripts/test_paycheck.sh
index bbec907..c395db4 100755
--- a/scripts/test_paycheck.sh
+++ b/scripts/test_paycheck.sh
@@ -125,7 +125,7 @@
   # Find paycheck.py
   paycheck=${0%/*}/paycheck.py
   if [ -z "${paycheck}" ] || [ ! -x ${paycheck} ]; then
-    die "cannot find paycheck.py or file is not executable"
+    die "cannot find ${paycheck} or file is not executable"
   fi
 
   # Check the payloads statically.