Duplicate username detection can false positive on the current user

[Jeff Godin]

Changing a username, then changing back to the user's current username results in a duplicate username detection -- a false positive due to the API call finding a user with that username -- the current user. This prevents you from saving any other changes you may have made to the user.

This can be prevented by skipping the duplicate username check if the user is not new and the username in the field matches the username stored in the in-memory Javascript representation of the user.

There's still a potential corner case which could be avoided by using a new/modified API call to either accept an "except this au.id" argument or to return the au.id of the found user, but I don't see a need for that at this point.

Working branch to follow.

[Jeff Godin (jgodin)]

working branch is user/jeff/fix_lp1246836_false_dupe_username

http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/jeff/fix_lp1246836_false_dupe_username

[Ben Shum (bshum)]

Works for me. Thanks Jeff!

I've picked this change to master, rel_2_5, and rel_2_4 with one minor modification (changed the git commit from "dup" to "duplicate")