suprising command line argument behaviour of `rebar3 release`

[sg2342]

when rebar3 release (or rebar3 tar) is executed with command line arguments --vm_args --sys_config --include_erts or --system_libs; the value provided on the command line is ignored unless the setting to be overriden is in relx config.

code responsible for this:

rebar3/apps/rebar/src/rebar_relx.erl

Lines 242 to 245 in b62659b

	replace_all_instance(Opt, Value, RelxConfig) ->
	lists:map(fun({K, _}) when K =:= Opt -> {K, Value};
	(Other) -> Other end, RelxConfig).

introduced in #2695