Remove deadbeef from usrsctp OWNERS and add orphis.

Change-Id: I802ac8a08a2e97e4cfac121108fc98611cb3bd70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2430289Reviewed-by: Tommi <tommi@chromium.org>
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811385}

third_party/usrsctp/OWNERS

-deadbeef@chromium.org
 hta@chromium.org
+orphis@chromium.org
 
 # COMPONENT: Internals>Networking