Allow Owners packages to have arbitrarily long names

Summary:

• Change column type from sort128 to sort.
• Remove originalName. This column is unused. Long ago, we used it to generate a Thread-Topic header for mail, but just use PHIDs now (the value just needs to be stable for a given object, users normally don't see it).

Test Plan:

• Created a package with a beautifully long name. Magnificent!
• Grepped for originalName / getOriginalName(), found no Owners hits.
• Verified that there isn't any name-length validation code to remove.

Reviewers: chad, amckinley

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D17798