spacecmd not working in Spacewalk 2.7?

Recently upgraded our Spacewalk 2.6 environment to 2.7, and spacecmd doesn't seem to work anymore. Whenever a user runs spacecmd, they get the following error:

Traceback (most recent call last):

  File "/usr/bin/spacecmd", line 135, in <module>

    files_read = config.read([_SYSTEM_CONF_FILE, user_conf_file, shell.options.config])

  File "/usr/lib64/python2.7/ConfigParser.py", line 302, in read

    fp = open(filename)

TypeError: coercing to Unicode: need string or buffer, NoneType found

I've tested this with several users, have tried clearing out any existing settings in ~/.spacecmd, and verified that /etc/spacecmd.conf doesn't exist, or is simply empty.

I've also managed to replicate this in a lab environment with a clean build of Spacewalk 2.7 on OEL 7.4.