fix `rebar3 shell` when relx section of rebar.config contains releases with independent configurations
fix `rebar3 shell` when relx section of rebar.config contains releases with independent configurations

djnym/rebar3,vladdu/rebar3,lrascao/rebar3,saleyn/rebar3,rebar/rebar3,rebar/rebar3,ferd/rebar3,erlang/rebar3,tsloughter/rebar3