Stop the logger properly in legacy commands

Ensures the logger is stopped on exit in legacy commands. Without this,
when using `nix-build --log-format bar` and stopping nix with CTRL+C,
the bar is not cleared from the screen.

src/nix-env/nix-env.cc

@@ -1489,8 +1489,6 @@ static int main_nix_env(int argc, char * * argv)
 
         globals.state->printStats();
 
-        logger->stop();
-
         return 0;
     }
 }