nfs4: Fix CID #1032280: Prevent integer overflow

* Do not increase delay after tenth attempt
 * Cast 1 to bigtime_t before shifting it left

src/add-ons/kernel/file_systems/nfs4/NFS4Object.cpp

@@ -17,9 +17,9 @@
 static inline bigtime_t
 RetryDelay(uint32 attempt, uint32 leaseTime = 0)
 {
-	attempt = min_c(attempt, sizeof(bigtime_t) * 8);
+	attempt = min_c(attempt, 10);
 
-	bigtime_t delay = (1 << (attempt - 1)) * 100000;
+	bigtime_t delay = (bigtime_t(1) << (attempt - 1)) * 100000;
 	if (leaseTime != 0)
 		delay = min_c(delay, sSecToBigTime(leaseTime));
 	return delay;