tests/io/test_file: rename test_open_file_read_lzma
tests/io/test_file: rename test_open_file_read_lzma

Rename to `test_open_file_write_lzma` so it doesn't override the
first `test_open_file_read_lzma` test.

nextstrain/augur,nextstrain/augur,nextstrain/augur