Fix default transaction timeout

Core/CkanTransaction.cs

@@ -26,7 +26,7 @@ public static TransactionScope CreateTransactionScope()
         }
 
         // System.ArgumentOutOfRangeException : Time-out interval must be less than 2^32-2. (Parameter 'dueTime')
-        private const double timeoutMs = 4294967294d;
+        private const double timeoutMs = Int32.MaxValue;
         private static readonly TimeSpan maxCoretimeout = TimeSpan.FromMilliseconds(timeoutMs);
 
         private static readonly TransactionOptions transOpts = new TransactionOptions()