Fix for Duplicate image src attributes in TinyMCE

This is a correction for the problem that is being discussed in the forum on Our at http://our.umbraco.org/forum/ourumb-dev-forum/bugs/39052-Duplicate-image-src-attributes

When an image could not be re-sized, its src attribute was being doubled. The attribute would be added in the catch clause of the relevant exception, and then it would also be re-added further down in the same method where the code is:

// Build image tag
foreach (var attr in allowedAttributes)
...

By commenting out the line of the catch clause which adds the src attribute, the issue has been resolved on my machine.

Please note that it is hard to reproduce this problem because the double src attribute does not actually appear in TinyMCE so there is no way to see it from there. The html source of the page needs to be reviewed.