build: Remove all generated RPC files from GIT

build: Remove all generated RPC files from GIT

Stop storing the generated files for the remote protocol client
and server in source control. The generated files will still be
included in the result of 'make dist' to avoid end-users needing
to generate the files

Signed-off-by: Eric Blake <eblake@redhat.com>
Unfortunately, this means that the strings marked for translation
in generated files are not picked up by gnulib's syntax-check,
I'm working on fixing that in gnulib.

* .gitignore, cfg.mk, po/POTFILES.in: Reflect deletion.