Changes in #1204, #1288 mistakenly changed the values for some error
defines, which breaks backward compatibility. (The WT_DEADLOCK error
name sorted differently from WT_ROLLBACK, and we were assigning error
values based on the sort order in a script.) Revert the change, and make
sure it doesn't happen again.
Merge pull request #1430 from wiredtiger/revert-error-value-change

Revert error return value changes.