module-vchan-sink: link up the card properly

[mattmccutchen]

Now the latency offset in pavucontrol works!

Addresses QubesOS/qubes-issues#1322.

I manually built the modified module-vchan-sink.so and hacked one AppVM to load it instead of the original, and it works. I haven't tried building RPMs, but I can't imagine that this small change would have a problem specific to the RPM build.

[mattmccutchen]

Here is my new GPG key for Qubes OS contributions: mattmccutchen-qubes-contributions.txt. (As explained here, I do not have a general-purpose GPG key at this time.) Do I need to do anything more before this key can be used, like submit a pull request to add it to signature-checker?

[mattmccutchen]

It looks like the Travis CI check failure is unrelated to my change:

Error unpacking rpm package qubes-core-agent-4.1.15-1.fc32.x86_64
error: unpacking of archive failed on file /etc/fstab;5f402261: cpio: rename failed - No such file or directory
error: qubes-core-agent-4.1.15-1.fc32.x86_64: install failed

[marmarek]

Thanks, I've uploaded your key to the signature-checker.

[mattmccutchen]

Thanks @marmarek! Since it may be a long time before Qubes 4.1 is released, would you be willing to apply this change to 4.0 as well? Let me know if I can help in some way. E.g., I could submit a pull request to the release4.0 branch, but I suspect it might be more work for you to review such a pull request than to just cherry-pick the commit yourself.

[marmarek]

No problem, should be in 4.0.30, just pushed to build server.