Turn off string interpolation on the FileStore class to avoid
exceptions when a value to be saved contains a percent sign (%).
The underlying SafeConfigParser that is used interprets percent
signs as placeholders to be interpolated which then causes an
exception as the placeholder isn't properly formatted.
ipa-client-install uses the FileStore class to backup certain
values that it overwrites as part of the installation. If those
pre-existing, backed-up values contained a percent sign,
ipa-client-install would throw an exception and thus prevent
installation.
https://pagure.io/freeipa/issue/9085
Reviewed-By: Rob Crittenden <rcritten@redhat.com>
ba796e389b