Adjust a test case so that the key isn't considered dummy

(len < 4)

Author: atorralba

go/ql/test/query-tests/Security/CWE-798/HardcodedCredentials.expected

@@ -25,4 +25,4 @@
 | main.go:44:14:44:19 | "p4ss" | Hard-coded $@. | main.go:44:14:44:19 | "p4ss" | password |
 | main.go:48:13:48:15 | tmp | Hard-coded $@. | main.go:44:14:44:19 | "p4ss" | password |
 | main.go:50:15:50:21 | "p4ss2" | Hard-coded $@. | main.go:50:15:50:21 | "p4ss2" | password |
-| sanitizer.go:18:44:18:46 | key | Hard-coded credential. | sanitizer.go:17:16:17:20 | `key` | password |
+| sanitizer.go:18:44:18:46 | key | Hard-coded credential. | sanitizer.go:17:16:17:25 | `some_key` | password |

go/ql/test/query-tests/Security/CWE-798/sanitizer.go

@@ -14,7 +14,7 @@ import (
 )
 
 func check_ok() (interface{}, error) {
-	key := []byte(`key`)
+	key := []byte(`some_key`)
 	return cristal.NewSignerHS(cristal.HS256, key) // BAD
 }