doveconf: Use key_ends_with to compare suffixes

Fixes key hiding.

Broken in 1518e08

src/config/doveconf.c

@@ -239,15 +239,23 @@ hide_url_userpart_from_value(struct ostream *output, const char **_ptr,
 	return TRUE;
 }
 
+static inline bool key_ends_with(const char *key, const char *eptr,
+				 const char *suffix)
+{
+	/* take = into account */
+	size_t n = strlen(suffix)+1;
+	return (eptr-key > (ptrdiff_t)n && str_begins(eptr-n, suffix));
+}
+
 static bool
 hide_secrets_from_value(struct ostream *output, const char *key,
 			const char *value)
 {
 	bool ret = FALSE, quote = value_need_quote(value);
 	const char *ptr, *optr, *secret;
 	if (*value != '\0' &&
-	    ((value-key > 8 && str_begins(value-9, "_password")) ||
-	     (value-key > 7 && str_begins(value-8, "_api_key")) ||
+	    (key_ends_with(key, value, "_password") ||
+	     key_ends_with(key, value, "_api_key") ||
 	     str_begins(key, "ssl_key") ||
 	     str_begins(key, "ssl_dh"))) {
 		o_stream_nsend_str(output, "# hidden, use -P to show it");