Artful pg-repack broken atm

[Christian Ehrhardt ]

It seems that a past update broke pg-repack.
Currently autopkgtest fail with issues like:

ERROR: unexpected index definition: CREATE UNIQUE INDEX testts1_pkey ON public.testts1 USING btree (id) TABLESPACE pg_default

Full example: https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-artful/artful/amd64/p/pg-repack/20180524_162608_a2d58@/log.gz

This is reproducible without proposed, just Artful as-is.

It is fixed in later pg-repack it seems, e.g. 1.4.2-2 in Bionic is good as-is with the new and old stable level of postgres (carries way more alternative repack_#.out files).

We could consider "just" updating the expected results of the tests, but that would just mask it.
So for now lets mask it as broken in britney hints (as this is what it really is on the current version).

To really fix one would need to drill down if/which part of past security MREs have broken this and if it really is valid. But given that there was not a single user-driven bug in that regard it might be just a lot of noise.

So while it is a valid bug I doubt that for the remaining 6 weeks we have with Artful one will spend a lot of effort unless there is a real user use-case impacted.

TL;DR: valid, but low prio, need to mark badtest to not block other SRUs