circleci: Remove Fedora Rawhide job

Rawhide is not stable and we already have a job for the latest stable
branch.

.circleci/config.yml

@@ -405,10 +405,6 @@ workflows:
           dist: fedora
           release: latest
           make_target: witness.dot
-      - build:
-          name: build_fedora_rawhide
-          dist: fedora
-          release: rawhide
       # latest debian uses sanitizers
       - build:
           name: build_debian_buster