ITS#7276 MozNSS: allow CA certdb together with PEM CA bundle file

Prior to this patch, if TLS_CACERTDIR was set to Mozilla NSS certificate
database and TLS_CACERT was set to a PEM bundle file with CA
certificates, the PEM file content was not loaded.

With this patch and the same settings, OpenLDAP can verify certificates
which are signed by CAs stored both in certdb and PEM bundle file.

libraries/libldap/tls_m.c

@@ -1683,18 +1683,28 @@ tlsm_deferred_init( void *arg )
 			ctx->tc_initctx = initctx;
 #endif
 
+		}
+
+		if ( errcode || lt->lt_cacertfile ) {
 			/* initialize the PEM module */
 			LDAP_MUTEX_LOCK( &tlsm_init_mutex );
 			if ( tlsm_init_pem_module() ) {
 				LDAP_MUTEX_UNLOCK( &tlsm_init_mutex );
-				errcode = PORT_GetError();
+				int pem_errcode = PORT_GetError();
 				Debug( LDAP_DEBUG_ANY,
 					   "TLS: could not initialize moznss PEM module - error %d:%s.\n",
-					   errcode, PR_ErrorToString( errcode, PR_LANGUAGE_I_DEFAULT ), 0 );
-				return -1;
+					   pem_errcode, PR_ErrorToString( pem_errcode, PR_LANGUAGE_I_DEFAULT ), 0 );
+
+				if ( errcode ) /* PEM is required */
+					return -1;
+
+			} else if ( !errcode ) {
+				tlsm_init_ca_certs( ctx, lt->lt_cacertfile, NULL );
 			}
 			LDAP_MUTEX_UNLOCK( &tlsm_init_mutex );
+		}
 
+		if ( errcode ) {
 			if ( tlsm_init_ca_certs( ctx, lt->lt_cacertfile, lt->lt_cacertdir ) ) {
 				/* if we tried to use lt->lt_cacertdir as an NSS key/cert db, errcode 
 				   will be a value other than 1 - print an error message so that the