fix metadata_v0 tests

The old metadata format didn't know anything of LiberapayID, so no need to
check for it.

.gitlab-ci.yml

@@ -25,6 +25,8 @@ metadata_v0:
     - git checkout $GITCOMMIT
     - cd fdroiddata
     - ../tests/dump_internal_metadata_format.py
+    - sed -i -e '/LiberapayID/d'
+          metadata/dump_*/*.yaml
     - diff -uw metadata/dump_*
 
 debian_testing: