changegroup: improve the devel-warn to specify changelog was empty Right now, the develwarn says "applied empty changegroup" which is not correct because we can send a changegroup without changelog with just manifest and filelogs and it will still say the same. Let's fix this to say that we are applying empty changelog from changegroup. In future patches I am will be adding functionality to send a changegroup from the server without an empty changelog. Differential Revision: https://phab.mercurial-scm.org/D4636