ECMsgTypes: fix constructor temp_added/temp_removed ordering to match users

Signed-off-by: Samuel Just <sam.just@inktank.com>
PGBackend/ECBackend: handle temp objects correctly

Signed-off-by: Samuel Just <sam.just@inktank.com>
ECBackend,ReplicatedPG: delete temp if we didn't get the transaction

We always send the transaction for operations on temp objects,
but if we didn't get the final transacition on the actual object,
we might end up failing to remove the temp object.  Thus, if
we get a sub op and don't have the transaction, just remove the
named temp objects.

Fixes: #7447
Signed-off-by: Samuel Just <sam.just@inktank.com>