koji_builder: Try using bootstrap

We may need to revert this if it causes issues, but try and enable
bootstrap mode again. Newer koji handles GC on these repos now and
it would help us out with a number of issues we are going to hit soon.

Signed-off-by: Kevin Fenzi <kevin@scrye.com>

roles/koji_builder/templates/builders/site-defaults.cfg

@@ -5,9 +5,5 @@ config_opts['macros']['%bugurl'] = 'https://bugz.fedoraproject.org/%name'
 config_opts['nosync'] = True
 config_opts['nosync_force'] = True
 config_opts['environment']['LANG'] = 'C.UTF-8'
-{% if env == 'staging' %}
 config_opts['use_bootstrap'] = True
-{% else %}
-config_opts['use_bootstrap'] = False
-{% endif %}
 config_opts['dnf_warning'] = False