run-tests.py: make tests use same python interpreter as test harness.
this is wanted because some tests run python interpreter directly.
must use same python interpreter in tests as in main harness or problems
will happen because of e.g. different python abi if run-tests.py run
with python 2.5 but system python is 2.4.
fix is to see if system python is used and is named python. if no,
put symlink called python at front of shell search path.
#!/bin/sh
hg init
echo "Is there an error message when trying to diff non-existing files?"
hg diff not found
echo "Is there an error message when trying to add non-existing files?"
hg add not found