httpd: don't install suid executables into nix store

Changed files
+1
pkgs
servers
http
thttpd
+1
pkgs/servers/http/thttpd/default.nix
···
prePatch = ''
sed -i -e 's/getline/getlineX/' extras/htpasswd.c
+
sed -i -e 's/chmod 2755/chmod 755/' extras/Makefile.in
'';
preInstall = ''