Use filetype start for some tests

These behave differently on Windows. Using the start of the filetype
make things pass everywhere

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

tests/data/filetest/archive/e.tar.gz.yml

@@ -1,5 +1,4 @@
-filetype_file: 'gzip compressed data, last modified: Tue Sep 9 01:32:36 2008, from Unix, original
-  size modulo 2^32 10240'
+filetype_file: gzip compressed data, last modified
 mimetype_file: application/gzip
 mimetype_python: application/x-tar
 is_file: yes