elixir: remove hardcoded certificate path for curl

The hardcoded CURL_CA_BUNDLE path does not exist on MacOS, which causes
all curl calls (e.g. in build scripts) to fail.  This commit removes
that environment variable, causing curl fall back to NIX_SSL_CERT_FILE
instead.

pkgs/development/interpreters/elixir/generic-builder.nix

@@ -46,8 +46,7 @@ in
        b=$(basename $f)
         if [ "$b" = mix ]; then continue; fi
         wrapProgram $f \
-          --prefix PATH ":" "${lib.makeBinPath [ erlang coreutils curl bash ]}" \
+          --prefix PATH ":" "${lib.makeBinPath [ erlang coreutils curl bash ]}"
-          --set CURL_CA_BUNDLE /etc/ssl/certs/ca-certificates.crt
       done
 
       substituteInPlace $out/bin/mix \