avoid dereferencing a NULL pointer by setting a default word to lookup in case

it is missing
CID 5 in the coverity.com scan

lib/dict.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2006, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -159,7 +159,8 @@ CURLcode Curl_dict(struct connectdata *conn, bool *done)
     }
 
     if ((word == NULL) || (*word == (char)0)) {
-      failf(data, "lookup word is missing");
+      infof(data, "lookup word is missing");
+      word=(char *)"default";
     }
     if ((database == NULL) || (*database == (char)0)) {
       database = (char *)"!";
@@ -213,7 +214,8 @@ CURLcode Curl_dict(struct connectdata *conn, bool *done)
     }
 
     if ((word == NULL) || (*word == (char)0)) {
-      failf(data, "lookup word is missing");
+      infof(data, "lookup word is missing");
+      word=(char *)"default";
     }
     if ((database == NULL) || (*database == (char)0)) {
       database = (char *)"!";