allow overwriting moves by default

Author: a-sully

index.bs

@@ -288,9 +288,6 @@ method steps are:
     1. Set |destinationEntry|'s [=entry/name=] to |newName|.
     1. If |entry| is [=the same as=] |destinationEntry|,
        [=/resolve=] |result| with `undefined`.
-     1. If |destinationEntry| exists in the underlying file system:
-       1. [=/Reject=] |result| with an "{{InvalidModificationError}}" {{DOMException}}
-           and abort.
 
   1. Let |accessSource| be the result of running |entry|'s
      [=entry/request access=] given "`readwrite`".
@@ -331,7 +328,7 @@ method steps are:
     1. If the underlying move operation throws an exception, [=/reject=]
        |result| with that exception and abort.
 
-     Issue(68): Better specify what possible exceptions this could throw.
+     Issue(11): Better specify what possible exceptions this could throw.
 
   1. Set |entry|'s [=entry/name=] to |newName|.