Support configuration-cache for S3Sync

[nedtwigg]

This plugin doesn't support configuration cache. There are two problems for S3Sync:

1. Easy to fix by injecting ObjectFactory and using ObjectFactory.fileTree().from(dir)
   

   gradle-aws-plugin-reboot/src/main/java/jp/classmethod/aws/reboot/gradle/s3/SyncTask.java

   Lines 131 to 138 in 072eedf

   	getProject().fileTree(source).visit(new EmptyFileVisitor() {
   	public void visitFile(FileVisitDetails element) {
   	es.execute(
   	new UploadTask(s3, element, bucketName, prefix, storageClass, acl, metadataProvider,
   	getLogger()));
   	}
   	});

2. Harder to fix
   

   gradle-aws-plugin-reboot/src/main/java/jp/classmethod/aws/reboot/gradle/s3/SyncTask.java

   Lines 112 to 113 in 072eedf

   	AmazonS3PluginExtension ext = getProject().getExtensions().getByType(AmazonS3PluginExtension.class);
   	AmazonS3 s3 = ext.getClient();

Not a big deal, very easy to just add --no-configuration-cache when doing an upload.

EDIT: P.S. Thanks for resurrecting this!