Description of problem:

When exporting on syncable format, the "listing" file is supposed to have permissions 644. If the user running the export command has an umask too restrictive, the permissions of the listing file will follow.

Version-Release number of selected component (if applicable):

How reproducible:
Always

Steps to Reproduce:
1. Set umask to 0077
2. export a repository/cv/library on syncable format
3. check the permissions of the file

Actual results: file is created with permissions based on the umask

Expected results: file should have 644 regardless of umask for the user running the command

Additional info: Users that do the export and simply copy/rsync the exported content keeping permissions may have issues on the disconnected side while trying to enable repositories.

QE Tracker for https://issues.redhat.com/browse/SAT-19662
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2233162