CameraService: Check Thread::run for failed threads.

While a thread failing to launch is somewhat catastrophic, checking the
result and printing the error / returning early is good practice.

Test: Ran CameraThreadSafetyTest.
Change-Id: I8c1d3fe197ef8af631960dd286096287de9a280e
diff --git a/services/camera/libcameraservice/common/Camera2ClientBase.cpp b/services/camera/libcameraservice/common/Camera2ClientBase.cpp
index e54813f..6f43270 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.cpp
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.cpp
@@ -147,10 +147,20 @@
 
     wp<NotificationListener> weakThis(this);
     res = mDevice->setNotifyCallback(weakThis);
+    if (res != OK) {
+        ALOGE("%s: Camera %s: Unable to set notify callback: %s (%d)",
+                __FUNCTION__, TClientBase::mCameraIdStr.string(), strerror(-res), res);
+        return res;
+    }
 
     /** Start watchdog thread */
     mCameraServiceWatchdog = new CameraServiceWatchdog();
-    mCameraServiceWatchdog->run("Camera2ClientBaseWatchdog");
+    res = mCameraServiceWatchdog->run("Camera2ClientBaseWatchdog");
+    if (res != OK) {
+        ALOGE("%s: Unable to start camera service watchdog thread: %s (%d)",
+                __FUNCTION__, strerror(-res), res);
+        return res;
+    }
 
     return OK;
 }