[sysadmin-bin] Skip mainline when generating refs

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit 35d60a0d585394606e3db2a359c7881777fc38b0
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Tue Oct 29 09:29:30 2019 +0100

    Skip mainline when generating refs

 git/post-receive-mirror-github | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/git/post-receive-mirror-github b/git/post-receive-mirror-github
index 235a504..8f8423b 100755
--- a/git/post-receive-mirror-github
+++ b/git/post-receive-mirror-github
@@ -231,7 +231,7 @@ def main():
     if github_settings['homepage'] != doap_settings['homepage']:
         gh.update_github_repo(repo_name, 'homepage', doap_settings["homepage"])
 
-    refs = ["refs/heads/{}".format(branch) for branch in doap_settings['branches'] if branch != "master"]
+    refs = ["refs/heads/{}".format(branch) for branch in doap_settings['branches'] if branch not in 
("master", "mainline")]
 
     github_repo_name = gh.normalize_name(repo_name)
     push_command = "git push --force git github com:{}/{} {}:mainline {}"