add release notes for bz887283

Change-Id: I20a468086e1927b1e46fc5d2e68b1292837432fc
Don't pass None to User.by_user_name() from System.change_loan()
Merge "Don't pass None to User.by_user_name() from System.change_loan()" into release-0.12
fix typo in d65e4a5a (numeric True -> False)
Fix for passing in invalid arch to distro import
Merge "add release notes for bz887283" into release-0.12