Comment out the line which causes IOS app crash when request expired wkh237#271

Author: wkh237

ios/RNFetchBlobNetwork.m

@@ -298,7 +298,8 @@ - (void) sendRequest:(__weak NSDictionary  * _Nullable )options
     UIBackgroundTaskIdentifier tid = [app beginBackgroundTaskWithName:taskId expirationHandler:^{
         NSLog([NSString stringWithFormat:@"session %@ expired", taskId ]);
         [expirationTable setObject:task forKey:taskId];
-        [app endBackgroundTask:tid];
+        // comment out this one as it might cause app crash #271
+//        [app endBackgroundTask:tid];
     }];
 
 }