[lint][fbcode/caffe2] CLANGFORMAT
Test Plan:
Proof of coverage:
```
$ hg files fbcode/caffe2 |
arc linttool debugfilterpaths --take CLANGFORMAT --path-match-only > ~/before.txt
$ hg up this_diff
$ hg files fbcode/caffe2 |
arc linttool debugfilterpaths --take CLANGFORMAT --path-match-only > ~/after.txt
$ comm -3 ~/before.txt ~/after.txt | pastry
P467377980: https://www.internalfb.com/intern/paste/P467377980/
```
These files lost coverage:
- `fbcode/caffe2/torch/abi-check.cpp`
- `fbcode/caffe2/torch/custom_class.h`
- `fbcode/caffe2/torch/custom_class_detail.h`
- `fbcode/caffe2/torch/deploy.h`
- `fbcode/caffe2/torch/extension.h`
- `fbcode/caffe2/torch/library.h`
- `fbcode/caffe2/torch/script.h`
Everything else in P467377980 gained coverage.
Reviewed By: suo
Differential Revision: D32364856
fbshipit-source-id: 9b3ba3350ecdb50038412a24af5e0da0fe4d69b8
