LZMA allows 9 levels of compression

In stream.c, the original lrzip source code takes compression level and factors it by 7/9 to conform to LZMA's standard of 7 levels. This was and is an error. LZMA allows 9 levels of compression.

old stream.c

	/* only 7 levels with lzma, scale them */
	lzma_level = control->compression_level * 7 / 9;
	if (!lzma_level)
		lzma_level = 1;