Bug#836342: UDD/testing_autoremovals_gatherer.pl: doesn't exclude non-release architectures

["Rebecca N. Palmer" <rebecca_palmer@zoho.com>]

Control: retitle -1 UDD/testing_autoremovals_gatherer.pl: includes non-release-architecture Build-Depends

The autoremoval listing went away when beignet 1.2.0 (which no longer
depends on LLVM 3.7 on any architecture) reached testing, and inspection
of the tool's source
(https://anonscm.debian.org/cgit/collab-qa/udd.git/tree/udd/testing_autoremovals_gatherer.pl)
appears to confirm that it doesn't check whether build-dependencies
apply on a release architecture.

(This means the bug could actually autoremove a package that shouldn't
be removed, but as arch-specific build-dependencies are likely to be
rare, I'm leaving it as minor.)