logd: syscall optimization

- prset(PR_SET_NAME) call once
- No need to call getuid(), should be AID_LOGD

Change-Id: I4dde0b178bc84e711b355cd7677b0dbf905a0634
diff --git a/logd/LogStatistics.cpp b/logd/LogStatistics.cpp
index accd660..6bb0b40 100644
--- a/logd/LogStatistics.cpp
+++ b/logd/LogStatistics.cpp
@@ -303,5 +303,5 @@
         }
         fclose(fp);
     }
-    return getuid(); // associate this with the logger
+    return AID_LOGD; // associate this with the logger
 }