templatekw: make getrenamed() return only filename, not nodeid
No callers cared about the nodeid and I want to make getrenamed() not
look up the node (although it's currently free, I hope to store copy
info in changesets and not include the nodeid).
Differential Revision: https://phab.mercurial-scm.org/D3666
#require clang-libfuzzer test-repo
$ cd $TESTDIR/../contrib/fuzz
$ make
Just run the fuzzer for five seconds to verify it works at all.
$ ./bdiff -max_total_time 5