Include all tests/*.py files in the MANIFEST so tests won't fail on tarballs.
This fixes failing test-http-proxy and test-webraw.
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -2,7 +2,7 @@ include hg
recursive-include mercurial *.py
include hgweb.cgi hgwebdir.cgi
include hgeditor rewrite-log
-include tests/README tests/coverage.py tests/run-tests.py tests/md5sum.py tests/test-*[a-z0-9] tests/*.out
+include tests/README tests/*.py tests/test-*[a-z0-9] tests/*.out
prune tests/*.err
include *.txt
include templates/map templates/map-*[a-z0-9]