tests: drop unnecessary force parameter for ebuild repo regen

Since pkgcraft now uses the provided custom cache dir for metadata
verification as well.

Author: radhermit

tests/repo/test_ebuild.py

@@ -120,7 +120,7 @@ def metadata_content(path):
 
         repo = TEST_DATA.repos["metadata"]
         # regenerate metadata to an external path
-        repo.metadata_regen(force=True, path=tmpdir)
+        repo.metadata_regen(path=tmpdir)
         # verify new data matches original
         data = sorted(metadata_content(tmpdir))
         assert data == sorted(metadata_content(repo.path.joinpath("metadata/md5-cache")))