Fix build

See r210927 and r210847


git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@211278 91177308-0d34-0410-b5e6-96231b3b80d8
Update for ScopStmt iterator name change in LLVM r210927

Contributed-by: Yabin Hu <yabin.hwu@gmail.com>

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@211280 91177308-0d34-0410-b5e6-96231b3b80d8