[CodeReview] Follow-up to r83345. I've updated svnImport.php to use CodeRepository::getDiffErrorMessage() when reporting the diff caching result, as it was basically duplicating the code from that function inline.
I've also tweaked getDiffErrorMessage() in the following ways:
- We now allow for the fact that the argument might actually be a valid diff, and in these cases we return an empty string (though I've added a TODO, for someone to check, as this may not be the best value to return).
- I've updated the function argument name to reflect the fact that it's not necessarily an error code any more.
- Added a case statement to handle DIFFRESULT_NothingToCompare, which was missing.
- Updated the strings to use the versions from svnImport, as these were a little more informative.
- Changed order of varname/type in documentation, as per wiki (http://www.mediawiki.org/wiki/Manual:Coding_conventions#Inline), due to Doxygen bug (https://bugzilla.gnome.org/show_bug.cgi?id=613185), and updated.