SVN didn't cooperate.
This doesn't work:
svn commit icon@2x.png -m "icon changed"
This is how to do it right:
svn commit icon@2x.png@ -m "icon changed"
Notice the added "@" in the end of the file name.
I hope this solves the problem in iPhone and iOS of how to commit the icon@2x.png file in SVN.
Good luck! :)