Subversion: Log allows clicks on non-revisions

The svn log allows to click on non-revisions and may display revision's text as a separate revision if the user provides bad commit messages.

e.g. for the screenshot:

• r19 is part of the text and clickable (and ends in a failed to retrieve revision)
• r6 is part of the (admittedly) bad commit message of r4 and is displayed as if it would be a revision (and is clickable as well)