Fix an incomplete null structure spec in Python readline suppression module.

Now that I'm building Linux with clang, I'm seeing more clang warnings.
This fills in some extra fields missing in the final end-of-structure-array
marker.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@211812 91177308-0d34-0410-b5e6-96231b3b80d8