Nit: fix range check in vcdecoder.cc

[maksverver]

In vcdecoder.cc, there is a check to see if the copy address falls within the decoded buffer:

open-vcdiff/src/vcdecoder.cc

Line 1194 in 868f459

if ((decoded_address < 0) || (decoded_address > here_address)) {

Here, the expression (decoded_address > here_address) should be replaced by (decoded_address >= here_address). Otherwise, if decoded_address == here_address, you'll go into an infinite loop here:

open-vcdiff/src/vcdecoder.cc

Lines 1221 to 1228 in 868f459

	while (size > (target_bytes_decoded - address)) {
	// Recursive copy that extends into the yet-to-be-copied target data
	const size_t partial_copy_size = target_bytes_decoded - address;
	CopyBytes(&target_segment_ptr[address], partial_copy_size);
	target_bytes_decoded += partial_copy_size;
	address += partial_copy_size;
	size -= partial_copy_size;
	}

This isn't a problem in practice, because VCDiffAddressCache already validates the returned address (correctly, this time):

open-vcdiff/src/addrcache.cc

Line 217 in 868f459

} else if (decoded_address >= here_address) {

So the check in vcdecoder.cc should be unnecessary. Still, if it's kept, it should be correct.