Don't require increased open file limit in solana-test-validator

Travis CI in particular does not allow the open file limit to be
increased.

ledger-tool/src/main.rs

@@ -615,7 +615,7 @@ fn open_blockstore(
     access_type: AccessType,
     wal_recovery_mode: Option<BlockstoreRecoveryMode>,
 ) -> Blockstore {
-    match Blockstore::open_with_access_type(ledger_path, access_type, wal_recovery_mode) {
+    match Blockstore::open_with_access_type(ledger_path, access_type, wal_recovery_mode, true) {
         Ok(blockstore) => blockstore,
         Err(err) => {
             eprintln!("Failed to open ledger at {:?}: {:?}", ledger_path, err);