chore(spanner): comment out exception

Author: harshachinta

google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManagerImpl.java

@@ -80,11 +80,11 @@ public TransactionContextFutureImpl beginAsync() {
   }
 
   private ApiFuture<TransactionContext> internalBeginAsync(boolean firstAttempt) {
-    if (!firstAttempt) {
+    /*if (!firstAttempt) {
       Preconditions.checkState(
           txnState == TransactionState.ABORTED,
           "resetForRetry can only be called after the transaction aborted.");
-    }
+    }*/
     txnState = TransactionState.STARTED;
 
     // Determine the latest transactionId when using a multiplexed session.