Install fails when /etc/rundeck is a symlink

The package install fails with the following message when /etc/rundeck is a symlink:

Unpacking replacement rundeck ...
Setting up rundeck (2.1.3) ...
usermod: no changes
chown: missing operand after rundeck:rundeck' Trychown --help' for more information.
dpkg: error processing rundeck (--install):
subprocess installed post-installation script returned error exit status 123
Errors were encountered while processing:
rundeck