Drop plugins from rebar.config when using rebar2

[bastien-fieldbox]

This patch is intended to be able to use this library with rebar2.
This error happened when running rebar get-deps.

WARN: Remote origin url is Cloning into 'prometheus'... Uncaught error in rebar_core: {'EXIT', {function_clause, [{code,which, [{rebar3_archive_plugin,"0.0.1"}], [{file,"code.erl"},{line,724}]}, {rebar_core,'-plugin_modules/3-lc$^0/1-0-', 1, [{file,"src/rebar_core.erl"},{line,570}]}, {rebar_core,plugin_modules,3, [{file,"src/rebar_core.erl"},{line,570}]}, {rebar_core,process_dir1,7, [{file,"src/rebar_core.erl"},{line,241}]}, {rebar_core,process_each,5, [{file,"src/rebar_core.erl"},{line,348}]}, {rebar_core,process_dir1,7, [{file,"src/rebar_core.erl"},{line,268}]}, {rebar_core,process_each,5, [{file,"src/rebar_core.erl"},{line,348}]}, {rebar_core,process_dir1,7, [{file,"src/rebar_core.erl"},{line,250}]}]}}

Regards

[bastien-fieldbox]

oops I pushed some local changes when trying to sign commit. reverted, sorry for the mess I don't understand all this new stuff on github.

Fun fact: if rebar2 see a .proto it will assume there is a protobuffs_compile module.

[essen]

Didn't try but the change looks fine.

Maybe squash the commits though, or cherry-pick when merging.

[essen]

Fun fact: if rebar2 see a .proto it will assume there is a protobuffs_compile module.

Perhaps the .proto files can be removed from the config.script as well.

[deadtrickster]

Protofiles used to generate the datamodel

[essen]

Yeah but they're not necessary to build and use prometheus.erl since the built Erlang files are also in the repository so removing them while doing a rebar2 build is fine. In Erlang.mk's case it simply ignores the .proto files, but since rebar2 isn't maintained I guess removing during rebar.config.script execution is the best solution.

[bastien-fieldbox]

So I am unconfortable to have a rebar.config.script that actually delete some source files.
What do you guys suggest? Maybe I could add the protobuff lib if rebar2?