Set CMake project name to THRIFT
Set CMake project name to THRIFT

Summary: CMake project names are normally uppercase as they are used as prefixes in things like `<PROJECT-NAME>_SOURCE_DIR`. Also we don't use the fb prefix in CMake variable names. Set the name to `THRIFT` to address this. Among other things this makes `THRIFT_SOURCE_DIR` introduced in D37840067 (https://github.com/facebook/fbthrift/commit/1f0c77cad902c28b6ed91f49e6560dc40b9e6186) work.

Reviewed By: Mizuchi

Differential Revision: D37857419

fbshipit-source-id: 58b5fc63765ab030e8a7ee00140228d91f4c28fb

facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift