add removed files to the changelog file list - this should allow better detection of removed file when walking in the history (like hg log) it doesn't help for the fast path of hg log where we only look at the filelog - users of the changelog file list shouldn't assume anymore that the file still exist (anyway it won't be found in the manifest like in 5ecf05541e11) - fix the tests (some hashes changed)

adding a
adding b
a
NONEXISTENT: No such file or directory
a
b
a: No such file or directory
NONEXISTENT: No such file or directory
b
a
NONEXISTENT: No such file in rev 9e1684505872
a
b