Adjust for Python-3.

Summary:
This does not yet give us a clean testsuite run but it does help with:
1. Actually building on linux
2. Run the testsuite with over 70% tests passing on linux.

Reviewers: tfiala, labath, zturner

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D17182

llvm-svn: 260721