RPKI-RTR: Missing break in switch (CID 1233099)

Change-Id: I01f01ce51fb1c9deb857ef01696b406b97dca3a9
Reviewed-on: https://code.wireshark.org/review/5616
Reviewed-by: Michael Mann <mmann78@netscape.net>
(cherry picked from commit 8c190d6db246ed2b212210b657f9705dfdc1b9d2)
Reviewed-on: https://code.wireshark.org/review/5639
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>