Fix test-notify for systems without or with a different version of diffstat.
Some diffstat versions say "1 file changed", others "1 files changed".
changeset: 0:9426b370c206
tag: tip
user: My Name <myname@example.com>
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
changeset: 1:4997f15a1b24
tag: tip
user: foo@bar.com
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
changeset: 2:72b8012b424e
tag: tip
user: foobar <foo@bar.com>
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
changeset: 3:35ff3067bedd
tag: tip
user: foo@bar.com
date: Mon Jan 12 13:46:40 1970 +0000
summary: commit-1
No username found, using user@host instead