Fix compilation error when we disable the LOGCAT.

Change-Id: I14294d113c6921419d55515bc14434b86d4a411d
diff --git a/lib/ExecutionEngine/FileHandle.cpp b/lib/ExecutionEngine/FileHandle.cpp
index 919cb48..1055ea7 100644
--- a/lib/ExecutionEngine/FileHandle.cpp
+++ b/lib/ExecutionEngine/FileHandle.cpp
@@ -37,7 +37,9 @@
 
   static int const lock_flags[2] = { LOCK_SH, LOCK_EX };
 
+#if USE_LOGGER
   static char const *const open_mode_str[2] = { "read", "write" };
+#endif
 
   static size_t const RETRY_MAX = 4;