Merge "tox: Silence output"

tox.ini

@@ -10,6 +10,8 @@ allowlist_externals =
 passenv =
   OS_TEST_DBAPI_ADMIN_CONNECTION
 setenv =
+  OS_STDOUT_CAPTURE=true
+  OS_STDERR_CAPTURE=true
   BASECOMMAND=stestr run
   {postgresql,all}: PIFPAF_POSTGRESQL=pifpaf -g OS_TEST_DBAPI_ADMIN_CONNECTION run postgresql --
   {mysql,all}: PIFPAF_MYSQL=pifpaf -g OS_TEST_DBAPI_ADMIN_CONNECTION run mysql --