Remove barbican-tempest-plugin from blacklist

This commit removes barbican-tempest-plugin from the blacklist. The
patch[1] got already merged. The plugin should work for the sanity now.

[1] https://review.opendev.org/#/c/634631/

Change-Id: I34d119c58afa6b3c728d1a540b4ea1df27d9c4d0
diff --git a/tools/generate-tempest-plugins-list.py b/tools/generate-tempest-plugins-list.py
index 255487e..64adcbe 100644
--- a/tools/generate-tempest-plugins-list.py
+++ b/tools/generate-tempest-plugins-list.py
@@ -35,8 +35,6 @@
 # TODO(masayukig): Some of these can be removed from BLACKLIST in the future
 # when the patches are merged.
 BLACKLIST = [
-    'openstack/barbican-tempest-plugin',
-    # https://review.opendev.org/#/c/634631/
     'x/gce-api',  # It looks gce-api doesn't support python3 yet.
     'x/group-based-policy',  # It looks this doesn't support python3 yet.
     'x/intel-nfv-ci-tests',  # https://review.opendev.org/#/c/634640/