Bug 81598 [Import/Export] Output tar files are too short
When outputting a small .tar file, I noticed that it was not correctly padded to 10240 bytes. The fix is to make sure we correctly close the output stream. This bug may have been exposed by the fix for 81277.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/TarOutputStream.java
public void closeEntry() throws IOException {
		byte[] data = new byte[512];
		int len = 512 - datapos;
		if(len > 0 && datapos > 0) {
			cursize = len;
			write(data,0,len);
		}
	}
	/**
	 *  The checksum of a tar file header is simply the sum of the bytes in
	 *  the header.
	 * 
	 * @param header
	 * @return checksum
	 */
	private long headerChecksum(byte[] header) {
		long sum = 0;
		for(int i = 0; i < 512; i++) {
			sum += header[i];
		}
		return sum;
	}
	/**
	 * Adds an entry for a new file in the tar archive.
	 * 
	 * @param e TarEntry describing the file
	 * @throws IOException
	 */
	public void putNextEntry(TarEntry e) throws IOException {
		byte[] header = new byte[512];