1. Happens on RHEL/Centos only(other distros are not affected)
2. Happens only during the first attempted install of ipa-client package. If we try to reinstall the sshd.conf is not modified.
3. We tried with --no-sshd flag to prevent sshd configuration
as suggested in the following ticket
[Freeipa-devel] [PATCH] 85 Add --no-ssh option to ipa-client-install to


We no longer get an messages in /var/log/ipaclientinstall.log about sshd.conf being backed up,  BUT 
the file still gets changed.