NSS: re-register NSS_Shutdown callback

Original upstream comment:

"""

When there's a persistent daemon for auth and it sets LDAP_OPT_X_TLS_NEWCTX, it

fails to auth at third login.

1. everything is good and destroyed after use but

tlsm_register_shutdown_callonce.initialized=1.

2. still good but because tlsm_register_shutdown_callonce.initialized==1, it

fails to register shutdown function.

   so pem_module is not destroyed at the end.

3. pem_module is not NULL so it's not initialized again and not added to modules

list. And Login fails.

"""

Sent-By: soohoon.lee@f5.com

Original-Name: soohoon-lee-160823.patch

Upstream-ITS: 8484

diff --git a/libraries/libldap/tls_m.c b/libraries/libldap/tls_m.c

index cdf7f8e..cf05914 100644

--- a/libraries/libldap/tls_m.c

+++ b/libraries/libldap/tls_m.c

@@ -1145,6 +1145,8 @@ tlsm_auth_cert_handler(void *arg, PRFileDesc *fd,

 	return ret;

 }

+static PRCallOnceType tlsm_register_shutdown_callonce = {0,0};

+

 static SECStatus

 tlsm_nss_shutdown_cb( void *appData, void *nssData )

 {

@@ -1157,10 +1159,15 @@ tlsm_nss_shutdown_cb( void *appData, void *nssData )

 		SECMOD_DestroyModule( pem_module );

 		pem_module = NULL;

 	}

+

+	/* init callonce so it can be armed again for cases like persistent daemon with LDAP_OPT_X_TLS_NEWCTX */

+	tlsm_register_shutdown_callonce.initialized = 0;

+	tlsm_register_shutdown_callonce.inProgress = 0;

+	tlsm_register_shutdown_callonce.status = 0;

+

 	return rc;

 }

-static PRCallOnceType tlsm_register_shutdown_callonce = {0,0};

 static PRStatus PR_CALLBACK

 tlsm_register_nss_shutdown_cb( void )

 {