SDAG: Use ReplaceNode here, not ReplaceUses

This was a typo in an earlier commit - there's no point in keeping the
old node around here.

Noticed by Meador Inge. Thanks!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269245 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed