kerberos: Add development string

+4
+2
pkgs/development/libraries/kerberos/heimdal.nix
··· 50 50 platforms = platforms.linux; 51 51 maintainers = with maintainers; [ wkennington ]; 52 52 }; 53 + 54 + passthru.implementation = "heimdal"; 53 55 }
+2
pkgs/development/libraries/kerberos/krb5.nix
··· 34 34 platforms = platforms.unix; 35 35 maintainers = with maintainers; [ wkennington ]; 36 36 }; 37 + 38 + passthru.implementation = "krb5"; 37 39 })