run-tests.py: tell coverage.py to ignore errors
Otherwise there'll be some IOErrors when it tries to open python
files created during the execution of e.g. test-hook.
#!/bin/sh
hg init
touch a
hg add a
hg ci -m "a" -d "1000000 0"
echo 123 > b
hg add b
hg diff --nodates
hg diff --nodates -r tip
echo foo > a
hg diff --nodates
hg diff -r ""
hg diff -r tip -r ""
true