GH-97: wait at least leaseDuration to acquire the lock

Fixes #97

This fixes an issue where `additionalTimeToWait` has a negative value
that is subtracted later by the Amazon DynamoDB client to
`leaseDuration`, making it impossible to acquire the lock if expired.

Also allow to use the existing `refreshPeriod` properties in this case.

* Use default refresh period in tryLock()

The 'refreshPeriod' value might not satisfy both tryLock() and lock()
requirements and should probably be used exclusively in the second case.

We can make the value used for tryLock() configurable as well in another
pull request.

* Rollback previous commit and add author name

Author: karllessard

src/main/java/org/springframework/integration/aws/lock/DynamoDbLockRegistry.java

@@ -60,6 +60,7 @@
  * Can create table in DynamoDB if an external {@link AmazonDynamoDBLockClient} is not provided.
  *
  * @author Artem Bilan
+ * @author Karl Lessard
  *
  * @since 2.0
  */
@@ -467,11 +468,11 @@ public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
 				return false;
 			}
 
-			long additionalTimeToWait = TimeUnit.MILLISECONDS.convert(time, unit) - System.currentTimeMillis() + start;
+			long additionalTimeToWait = Math.max(TimeUnit.MILLISECONDS.convert(time, unit) - System.currentTimeMillis() + start, 0L);
 
 			this.acquireLockOptionsBuilder
 					.withAdditionalTimeToWaitForLock(additionalTimeToWait)
-					.withRefreshPeriod(0L);
+					.withRefreshPeriod(DynamoDbLockRegistry.this.refreshPeriod);
 
 			boolean acquired = false;
 			try {