clean-old-stack-libs.sh: lts-14.27 and use cd/pwd
clean-old-stack-libs.sh: lts-14.27 and use cd/pwd

simonmichael/stackage,soenkehahn/stackage,massysett/stackage,mrkkrp/stackage,asr/stackage,jonschoning/stackage,michalkonecny/stackage,clinty/stackage,fpco/stackage,iand675/stackage,Daniel-Diaz/stackage