OpenTripPlanner does not accept all protobuf content-type options

[optionsome]

Expected behavior

OpenTripPlanner should accept application/x-protobuf for protobuf files. There might be some other content-type options that are in use for protobuf files that #2797 does not account for.

Observed behavior

406 error is returned when fetching realtime data with Content-Type: application/x-protobuf

Version of OTP used (exact commit hash or JAR name)

1.5.0

Steps to reproduce the problem

Unfortunately the realtime feeds I have this issue with (more than one) are not public

[optionsome]

Because #2797 include */* in Accept header, it should work on most web servers. However, seems like the server I'm dealing with is poorly configured or buggy. Tried adding application/x-protobuf to Accept header but the issue still persists. Trying to get information about the system where the feed is published but right now it does not seem like this issue could be fixed in OTP by other means than by removing the header but I can circumvent this issue in our system. Unless other users are dealing with similar issues, I'm not sure if we should change anything in OTP code.

[optionsome]

Actually there is an issue with OTP code. The separator for different mime types is wrong. It should be ,, not ;