createDirectory() with empty path ("")

[stefanofornari]

in S3FileSystemProvider.createDirecotry()

aws-java-nio-spi-for-s3/src/main/java/software/amazon/nio/spi/s3/S3FileSystemProvider.java

Lines 343 to 346 in e831e67

	String directoryKey = s3Path.toRealPath(NOFOLLOW_LINKS).getKey();
	if (!directoryKey.endsWith(S3Path.PATH_SEPARATOR) && !directoryKey.isEmpty()) {
	directoryKey = directoryKey + S3Path.PATH_SEPARATOR;
	}

we may throw an exception if Path.getKey() returns an empty (the root) string.

[markjschreiber]

Agree, we should also throw an exception if the input Path is null

[markjschreiber]

Fixed in main