context: make sure file is not deleted while checking path conflicts
If a file is deleted and a directory of same name is created in the same commit,
IMM thinks of that as a file conflict, however the file is deleted and hence the
directory can be created.
The test change demonstrate the fix.
Differential Revision: https://phab.mercurial-scm.org/D4300
cat >> $HGRCPATH <<EOF
[extensions]
narrow=
[ui]
ssh=python "$TESTDIR/dummyssh"
[experimental]
changegroup3 = True
EOF