cookie: Fix bug in export if any-domain cookie is present

In 3013bb6b I had changed cookie export to ignore any-domain cookies,
however the logic I used to do so was incorrect, and would lead to a
busy loop in the case of exporting a cookie list that contained
any-domain cookies. The result of that is worse though, because in that
case the other cookies would not be written resulting in an empty file
once the application is terminated to stop the busy loop.

lib/cookie.c

@@ -1274,9 +1274,8 @@ static int cookie_output(struct CookieInfo *c, const char *dumphere)
           "# http://curl.haxx.se/docs/http-cookies.html\n"
           "# This file was generated by libcurl! Edit at your own risk.\n\n",
           out);
-    co = c->cookies;
 
-    while(co) {
+    for(co = c->cookies; co; co = co->next) {
       if(!co->domain)
         continue;
       format_ptr = get_netscape_format(co);
@@ -1288,7 +1287,6 @@ static int cookie_output(struct CookieInfo *c, const char *dumphere)
       }
       fprintf(out, "%s\n", format_ptr);
       free(format_ptr);
-      co=co->next;
     }
   }
 
@@ -1309,9 +1307,7 @@ struct curl_slist *Curl_cookie_list(struct SessionHandle *data)
       (data->cookies->numcookies == 0))
     return NULL;
 
-  c = data->cookies->cookies;
-
-  while(c) {
+  for(c = data->cookies->cookies; c; c = c->next) {
     if(!c->domain)
       continue;
     line = get_netscape_format(c);
@@ -1326,7 +1322,6 @@ struct curl_slist *Curl_cookie_list(struct SessionHandle *data)
       return NULL;
     }
     list = beg;
-    c = c->next;
   }
 
   return list;