CVSREADONLYFS and run-tests.py interaction

[Giorgos Keramidas]

CVS in FreeBSD and a few other systems (e.g. a Debian server I am often
using) supports a CVSREADONLYFS environment option that may be set to
turn cvs(1) into a read-only client.  If this is set in the runtime
environment of our "run-tests.py" script, the cvs conversion tests fail
because they cannot commit to the test repositories.

Does something like the following patch look ok?  I didn't see any other
del invocations in run-tests.py, so the placement may not be optimal,
but it seems to work for the tests I ran locally.

%%%
diff -r b57ea947b646 tests/run-tests.py
--- a/tests/run-tests.py        Mon Jan 04 06:23:45 2010 +0200
+++ b/tests/run-tests.py        Wed Jan 13 02:37:25 2010 +0200
@@ -821,6 +821,8 @@ def main():
     os.environ['CDPATH'] = ''
     os.environ['COLUMNS'] = '80'
     os.environ['http_proxy'] = ''
+    if 'CVSREADONLYFS' in os.environ:
+        del os.environ['CVSREADONLYFS']
 
     global TESTDIR, HGTMP, INST, BINDIR, PYTHONDIR, COVERAGE_FILE
     TESTDIR = os.environ["TESTDIR"] = os.getcwd()
%%%