Changes

publish-tarballs-for-tags.sh: publish osmo-epdg's versions

To have explicit different tags for strongswan and not to clash
against the upstream tag, use prefix osmo-epdg for tags.
0.1.0 -> osmo-epdg-0.1.0.

osmo-epdg tags will follow the common version pattern (0.1.0).

Change-Id: I3445e76f6fd6ebb49ada5dc4320c6b9fa717f00c