remotefilelog: fix {file_copies} template keyword remotefilelog overrides templatekw.getrenamedfn(). I changed the return type of that function in ec37df9042f9 (templatekw: make getrenamed() return only filename, not nodeid, 2018-03-26). So we need to change remotefilelog too. The function is used by the {file_copies} template keyword and by `hg log --copies`. Differential Revision: https://phab.mercurial-scm.org/D5576

tests: demonstrate broken {file_copies} template with remotefilelog Differential Revision: https://phab.mercurial-scm.org/D5575