Only delete ebin when fetching Erlang.mk projects
Only delete ebin when fetching Erlang.mk projects

Erlang.mk projects either have a .app.src, or just the Makefile
with an optional .app file for compatibility.

ingwinlu/erlang.mk,hairyhum/erlang.mk,rabbitmq/erlang.mk,nevar/erlang.mk,jj1bdx/erlang.mk,ninenines/erlang.mk,crownedgrouse/erlang.mk