Ticket #321 - krbExtraData is being null modified and replicated on each ssh login
Bug Description: Crash during IPA install
Fix Description: Have to free the mod before moving the unremoved mods
down the list on top of the freed mod.
Reviewed by: mreynolds (Thanks!)
(cherry picked from commit 758a68db83c653187203d683c9d9a71742314be5)