Fixed NPE inside org.webrtc.Camera1Session.create

On some devices `android.hardware.Camera.open` returns null
instead of raising exception. It causes `NPE` inside
`Camera1Session.create` when method `setPreviewTexture` is
invoked on local variable `camera`, which is `null`.

Bug: webrtc:8658
Change-Id: Ic65b4aef2c0b8b65735a9db02433b536bfe92ddd
Reviewed-on: https://webrtc-review.googlesource.com/33620
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21352}
diff --git a/AUTHORS b/AUTHORS
index 121838f..abf8b5b 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -55,6 +55,7 @@
 Victor Costan <costan@gmail.com>
 Xiaohong Xu <freemine@yeah.net>
 Xiaolei Yu <dreifachstein@gmail.com>
+Yura Yaroshevich <yura.yaroshevich@gmail.com>
 Hans Knoechel <hans@hans-knoechel.de>
 Korniltsev Anatoly <korniltsev.anatoly@gmail.com>