[pptp-server] PPP modules for MPPE

[Jim Roland]

When I had this problem under RH70, I went to RH71 due to compilation
errors.  Both versions of distro had a "quirk" with the kernel in that you
had to do an "mrproper" to force the symbol table to be exported and built.
Here is what I did (I believe) to correct this issue:

Backup your ".config" file from the /usr/src/linux* directory, back it up to
/usr/src directory.