Set cg_file_data_ to null when initialization failed

Cannot really do calls if initialization failed.
Also fix LOG usage.

But: 124774415
Test: Build
Change-Id: Ifd7db90cfee51ba5830e1d4db8f8d19b5bc9feba
diff --git a/libprocessgroup/sched_policy.cpp b/libprocessgroup/sched_policy.cpp
index 026c011..1eefada 100644
--- a/libprocessgroup/sched_policy.cpp
+++ b/libprocessgroup/sched_policy.cpp
@@ -167,7 +167,7 @@
     if (!controller) return -1;
 
     if (!controller->GetTaskGroup(tid, &subgroup)) {
-        PLOG(ERROR) << "Failed to find cgroup for tid " << tid;
+        LOG(ERROR) << "Failed to find cgroup for tid " << tid;
         return -1;
     }
     return 0;