shell.nix: Remove obsolete flags
shell.nix: Remove obsolete flags

pikajude/nix,peti/nix,peti/nix,dtzWill/nix,rycee/nix,rycee/nix,zimbatm/nix,shlevy/nix,shlevy/nix,shlevy/nix,zimbatm/nix,vcunat/nix,rycee/nix,layus/nix,layus/nix,shlevy/nix,layus/nix,ehmry/nix,layus/nix,pikajude/nix,NixOS/nix,vcunat/nix,ehmry/nix,bennofs/nix,dtzWill/nix,NixOS/nix,vcunat/nix,vcunat/nix,rycee/nix,ehmry/nix,ehmry/nix,dezgeg/nix,peti/nix,bennofs/nix,dezgeg/nix,dtzWill/nix,ehmry/nix,peti/nix,NixOS/nix,bennofs/nix,rycee/nix,NixOS/nix,dezgeg/nix,zimbatm/nix,bennofs/nix,pikajude/nix,zimbatm/nix,shlevy/nix,peti/nix,dtzWill/nix,dtzWill/nix,dezgeg/nix,layus/nix,ehmry/nix,NixOS/nix,dezgeg/nix