Make black ignore imported python files used to build hosts releases

While building releases, a pile of python gets imported into the
per-host directories. If black gets run afterwards, it tries to go
'fix' all of that stuff. Ignore those files to avoid doing that.

Signed-off-by: Keith Packard <keithp@keithp.com>

Makefile

@@ -36,7 +36,7 @@ FORCE:
 
 check: all
 	+cd test && make $@
-	+black --check --exclude 'fail-syntax-.*\.py' .
+	+black --check --exclude 'fail-syntax-.*\.py|.*/hosts/.*.py' .
 
 SHAREFILES = \
 	snek.defs \