logd: remove class LogCommand, rename LogCommand.cpp to LogPermissions.cpp

class LogCommand isn't needed, so remove it.  Since the rest of
LogCommand.cpp only has to do with permissions, rename it
appropriately.

Test: logging unit tests
Change-Id: I32d09c74d00b6e50083e46832eca3dd886b46682
diff --git a/logd/LogReader.cpp b/logd/LogReader.cpp
index c69e4bd..89562a4 100644
--- a/logd/LogReader.cpp
+++ b/logd/LogReader.cpp
@@ -30,6 +30,7 @@
 
 #include "LogBuffer.h"
 #include "LogBufferElement.h"
+#include "LogPermissions.h"
 #include "LogReader.h"
 #include "LogUtils.h"
 #include "LogWriter.h"