remove bogus logging passing `None` to `utils.stdout()`

Summary:`exc.output` can be (always is?) `None`. Other places in the code only print
using `traceback.print_exc()` and this was the only place trying to print this
extra info (`git grep CalledProcessError`). This caused `utils.stdout()` to
raise an exception, which was further confusing.

closes #330

Reviewed By: jberdine

Differential Revision: D3203896

fb-gh-sync-id: d2988d8
fbshipit-source-id: d2988d8

infer/lib/python/inferlib/capture/xcodebuild.py

@@ -75,5 +75,4 @@ class XcodebuildCapture:
         except subprocess.CalledProcessError as exc:
             if self.args.debug:
                 traceback.print_exc()
-            utils.stdout(exc.output)
             return exc.returncode