Windows: rename compile_et.pod to afs_compile_et.pod

Windows: rename compile_et.pod to afs_compile_et.pod

Gerrit 175 renamed compile_et and compile_et.pod to afs_compile_et*.
Fix the Windows build system to process the new pod file name
and modify the WiX installer scripts to install afs_compile_et.html.

FIXES 125152

LICENSE MIT

Reviewed-on: http://gerrit.openafs.org/http://gerrit.openafs.org/204
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>