Remove variable output affected by length of TMPDIR.
If the temporary directory is longer than /tmp then it's possible that
the Subject line will get wrapped by the headencode function.
#!/bin/sh
# http://mercurial.selenic.com/bts/issue433
hg init a
cd a
echo a > a
hg commit -Ama
hg parents -r 0 doesnotexist
true