Merge branch 'jk/drop-hg-to-git'

Remove an ancient and not well maintained Hg-to-git migration script from contrib/. Acked-by: Stelian Pop <stelian@popies.net> cf. <37e4cd61-b370-437e-bd42-f98f47d3ad32@popies.net> * jk/drop-hg-to-git: contrib: drop hg-to-git script