swift234

fix <rdar://problem/19833424> QoI: Bad error message when using Objective-C literals (@"Hello") in Swift files

Before:

t.swift:2:9: error: expected initial value after '='
let x = @"foo"
        ^
t.swift:2:8: error: consecutive statements on a line must be separated by ';'
let x = @"foo"
       ^
       ;
t.swift:2:10: error: expected an attribute name
let x = @"foo"
         ^
t.swift:2:10: error: expected declaration
let x = @"foo"
         ^

now:

t.swift:2:9: error: string literals in Swift are not preceeded by an '@' sign
let x = @"foo"
        ^



Swift SVN r28698