When doing an insert into a sharded collection because of SERVER-4381 but in attached testcase it does not properly set "err:" field and "code:" field when writeback listeners are involved.

Before fix for SERVER-4532 and SERVER-7958 the attached code would set err: but not code: fields (so it would fail in the first failed asserts before split/migration) however testing it with both of those fixes now it returns proper GLE before split/migrate but after returns:

assert failed : Insert of a duplicate record after split/migrate did not create correct GLE{
"singleShard" : "localhost:30000",
"n" : 0,
"connectionId" : 21,
"err" : null,
"ok" : 1,
"code" : 11000,
"writebackGLE" :

{ "singleShard" : "localhost:30000", "n" : 0, "connectionId" : 21, "err" : null, "ok" : 1 }

,
"initialGLEHost" : "localhost:30000",
"initialGLE" : {
"err" : "E11000 duplicate key error index: test.trans.$owner_1 dup key: { : 1234567890 }",
"code" : 11000,
"n" : 0,
"connectionId" : 16,
"ok" : 1
}
}