packaging: setup: using a different filename for remote wsp certs

Proposing a different filename for remote WebSocket proxy cert
to avoid overriding existing files.

Change-Id: I5304796d6a7df07cc403a9de094ddf3edf6e5208
Bug-Url: https://bugzilla.redhat.com/1116036
Signed-off-by: Simone Tiraboschi <stirabos@redhat.com>
(cherry picked from commit 291e933574873a4b568fb0c9c4381c0d4d82db9b)