ngOptions inserts empty option with one-time bindings

[bukharin]

ngOptions with one-time binding inserts an empty option in onblur event

jsFiddle: http://jsfiddle.net/bukharin/7yENP/4/

v.1.3.0-beta.13

[caitp]

Yeah, so currently bind-once makes a copy of the object, and so the object values never match the one in scope. #7700 removes the copy, among a lot of other things, so once we can check that in, this should be fixed. I'll ask @rodyhaddad to add a test case for this issue