SubmitRecords used to have a RULE_ERROR status code. That was
mainly used to signal errors caused by the Prolog interpreter.
These are user-caused errors (caused by wrong Prolog code).
This use is fine as-is and can be expanded to other rules such
as the code-owners rule.
However, over time, this error code was used also to signal
server-errors - such as lookup failures for labels or project
state. This not not a good use because server errors should
always propagate as HTTP 500 errors and also prevent and
index document with a broken SubmitRecord to be created.
This commit cleans this space up and reserves the RULE_ERROR
for user-caused issues.
Change-Id: I018ce9e13fa40f2f24546df49ecf7fc3fbb72b1b
(cherry picked from commit fa8d17768b2558ec44a2b183bfee4508b0f3228a)
8a6c1b8600