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.

tests/test-notify-changegroup

@@ -1,43 +1,43 b''
 #!/bin/sh
 
 cat <<EOF >> $HGRCPATH
 [extensions]
 notify=
 
 [hooks]
 changegroup.notify = python:hgext.notify.hook
 
 [notify]
 sources = push
 diffstat = False
-maxsubject = 200
+maxsubject = 10
 
 [usersubs]
 foo@bar = *
 
 [reposubs]
 * = baz
 EOF
 
 hg init a
 
 echo % clone
 hg --traceback clone a b
 
 echo a > b/a
 echo % commit
 hg --traceback --cwd b commit -Ama
 
 echo a >> b/a
 echo % commit
 hg --traceback --cwd b commit -Amb
 
 echo % push
 hg --traceback --cwd b push ../a 2>&1 |
     python -c 'import sys,re; print re.sub("\n\t", " ", sys.stdin.read()),' |
     sed -e 's/\(Message-Id:\).*/\1/' \
         -e 's/changeset \([0-9a-f]* *\)in .*test-notif/changeset \1in test-notif/' \
-        -e 's/^Subject: .*test-notify/Subject: test-notify/' \
+        -e 's/^Subject: .*/Subject: test-notify-changegroup/' \
         -e 's/^details: .*test-notify/details: test-notify/' \
         -e 's/^Date:.*/Date:/'
 

tests/test-notify-changegroup.out

@@ -1,39 +1,39 b''
 % clone
 updating to branch default
 0 files updated, 0 files merged, 0 files removed, 0 files unresolved
 % commit
 adding a
 % commit
 % push
 pushing to ../a
 searching for changes
 adding changesets
 adding manifests
 adding file changes
 added 2 changesets with 2 changes to 1 files
 Content-Type: text/plain; charset="us-ascii"
 MIME-Version: 1.0
 Content-Transfer-Encoding: 7bit
 Date:
-Subject: test-notify-changegroup/a: 2 new changesets
+Subject: test-notify-changegroup
 From: test
 X-Hg-Notification: changeset cb9a9f314b8b
 Message-Id:
 To: baz, foo@bar
 
 changeset cb9a9f314b8b in test-notify-changegroup/a
 details: test-notify-changegroup/a?cmd=changeset;node=cb9a9f314b8b
 summary: a
 
 changeset ba677d0156c1 in test-notify-changegroup/a
 details: test-notify-changegroup/a?cmd=changeset;node=ba677d0156c1
 summary: b
 
 diffs (6 lines):
 
 diff -r 000000000000 -r ba677d0156c1 a
 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
 +++ b/a	Thu Jan 01 00:00:00 1970 +0000
 @@ -0,0 +1,2 @@
 +a
 +a