tests/blacklists/linux-vfat

clone: avoid using repo.lookup() with binary nodeid

The code in hg.clone() is a bit of a mess, but it seems like the
"checkout" variable is always a binary nodeid (tests pass when run
with "assert len(checkout) == 20" before the
repo.lookup()). repo.lookup() will soon work only with string inputs,
so we need remove this use.

Differential Revision: https://phab.mercurial-scm.org/D3191

# invalid filenames
test-add.t
test-init.t
test-clone.t
test-contrib.t
test-hgweb-raw.t
test-walk.t

# no sockets or fifos
test-hup.t

# no hardlinks
test-hardlinks.t
test-relink.t

# exec bit problems
test-convert-bzr-114.t
test-convert-bzr-directories.t
test-convert-bzr-merges.t
test-convert-bzr-treeroot.t
test-convert-darcs.t
test-merge-tools.t

# debugstate exec bit false positives
test-dirstate.t
test-filebranch.t
test-merge-remove.t