[Debian-med-packaging] stacks is marked for autoremoval from testing

[Debian testing autoremoval watch]

stacks 2.2+dfsg-1 is marked for autoremoval from testing on 2018-12-31

It (build-)depends on packages with these RC bugs:
911492: htslib, src:python-pysam: htslib breaks python-pysam autopkgtest