Don't attempt to write recovery.conf when -R is not specified

Fixes segmentation fault during regular use.

Fujii Masao

src/bin/pg_basebackup/pg_basebackup.c

@@ -1084,7 +1084,7 @@ ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum)
 	if (copybuf != NULL)
 		PQfreemem(copybuf);
 
-	if (basetablespace)
+	if (basetablespace && writerecoveryconf)
 		WriteRecoveryConf();
 }