Tracking ToT changes in DIBuilder interface

LLVM commit r176004 changed DIBuilder::createStructType() interface:

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130218/166758.html

One more argument was added.

Here's an example of how interface client were updated in clang:

http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20130218/074876.html