hwc: Return failure from hwc_device_open when fb open fails

- When fb open fails during hwc initialization, it should be
  flagged as a fatal error and HAL should return error.
- Without this, the SF would make calls to HWC that would fail,
  and display being blank.

Change-Id: I20f08bdcb283d4805449c74a8214b871c2f1c80b
diff --git a/libhwcomposer/hwc.cpp b/libhwcomposer/hwc.cpp
index bf59217..496798a 100644
--- a/libhwcomposer/hwc.cpp
+++ b/libhwcomposer/hwc.cpp
@@ -966,7 +966,11 @@
         memset(dev, 0, sizeof(*dev));
 
         //Initialize hwc context
-        initContext(dev);
+        status = initContext(dev);
+        if (status < 0) {
+            free(dev);
+            return status;
+        }
 
         //Setup HWC methods
         dev->device.common.tag          = HARDWARE_DEVICE_TAG;