Fix more build errors in Polly after r206310. David caught one of these
in r206312, but others don't seem to show up on build bots? Unsure of
why, they showed up for me.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@206326 91177308-0d34-0410-b5e6-96231b3b80d8