tests: don't log manifest-file in test-strip-cross.t
I'm confident that the file is there only to help produce a certain
manifest log; there is nothing special about the file's filelog
itself. (And there already is a `hg debugindex --manifest` call higher
up in the file that shows the crossed linkrevs.)
Differential Revision: https://phab.mercurial-scm.org/D6791
$ hg init
$ touch unknown
$ touch a
$ hg add a
$ hg ci -m "1"
$ touch b
$ hg add b
$ hg ci -m "2"
Should show unknown
$ hg status
? unknown
$ hg revert -r 0 --all
removing b
Should show unknown and b removed
$ hg status
R b
? unknown
Should show a and unknown
$ ls
a
unknown