Fix line numbers for new post-image comments in unified view

The line numbers we were using to create new post-image comment
editors in the unified diff view were wrong.  Due to a simple
copy and paste error we were using the old (aka pre-image) line
number for the line, which always caused the comment to appear
in the wrong location later on, even though we showed it at the
right location initially.

Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed