Editing symlinked file is replacing the link with the edited file

[porter]

Using the "Edit" feature on a symbolic link to a file loads the contents of the linked file into the editor, but upon saving the symbolic link itself is being replaced with a standard file rather than the linked file being updated with the edited contents.

I don't know if this is really just a facet of #1860, but it seems like either editing of symlinked files shouldn't be allowed, or the links should be traversed in both directions, when loading and when saving.

[dkocher]

In r15102.