[PATCH][docs] Update URL of greek-tree.txt in repro-template.sh

Hi!

A comment at the top of repro-template.sh [1] (referenced from [2]) contains URL
of the greek-tree.txt file. The URL points to svn.collab.net site and
is no more valid.
I am attaching a patch to correct this.

 [1]: http://subversion.apache.org/docs/community-guide/repro-template.sh
 [2]: http://subversion.apache.org/docs/community-guide/issues.html#reporting-bugs

The patch is to be applied to
https://svn.apache.org/repos/asf/subversion/site/publish

[[[
Update URL in a comment in repro-template.sh to point to svn.apache.org
repository, instead of the old collab.net one.

* docs/community-guide/repro-template.sh: Update URL.
]]]

Best regards,
Konstantin Kolinko