- Kevin Baughman provided a fix preventing libcurl-NSS from crash on doubly

closed NSPR descriptor. The issue was hard to find, reported several times
  before and always closed unresolved. More info at the RH bug:
  https://bugzilla.redhat.com/534176

lib/nss.c

@@ -1227,7 +1227,9 @@ CURLcode Curl_nss_connect(struct connectdata *conn, int sockindex)
   connssl->handle = SSL_ImportFD(model, connssl->handle);
   if(!connssl->handle)
     goto error;
+
   PR_Close(model); /* We don't need this any more */
+  model = NULL;
 
   /* This is the password associated with the cert that we're using */
   if (data->set.str[STRING_KEY_PASSWD]) {