ipa-replica-install: properly use the file store
    
    In ipa-replica-install, many components use their own instance
    of the FileStore to backup configuration files to the pre-install
    state. This causes issues when the calls are mixed, like for
    instance:
    ds.do_task1_that_backups_file (using ds.filestore)
    http.do_task2_that_backups_file (using http.filestore)
    ds.do_task3_that_backups_file (using ds.filestore)
    
    because the list of files managed by ds.filestore does not include
    the files managed by http.filestore, and the 3rd call would remove
    any file added on 2nd call.
    
    The symptom of this bug is that ipa-replica-install does not save
    /etc/httpd/conf.d/ssl.conf and subsequent uninstallation does not
    restore the file, leading to a line referring to ipa-rewrite.conf
    that prevents httpd startup.
    
    The installer should consistently use the same filestore.
    
    Fixes https://pagure.io/freeipa/issue/7684
    
    Reviewed-By: Christian Heimes <cheimes@redhat.com>