Libutils: Comment out unused constants

For build-system CFLAGS clean-up, "remove" unused variables.

Change-Id: Ic96f066981cd96ca16af81ee3fdbc972507e8c81
diff --git a/libutils/Unicode.cpp b/libutils/Unicode.cpp
index d9334f7..fb876c9 100644
--- a/libutils/Unicode.cpp
+++ b/libutils/Unicode.cpp
@@ -40,8 +40,9 @@
 // Surrogates aren't valid for UTF-32 characters, so define some
 // constants that will let us screen them out.
 static const char32_t kUnicodeSurrogateHighStart  = 0x0000D800;
-static const char32_t kUnicodeSurrogateHighEnd    = 0x0000DBFF;
-static const char32_t kUnicodeSurrogateLowStart   = 0x0000DC00;
+// Unused, here for completeness:
+// static const char32_t kUnicodeSurrogateHighEnd = 0x0000DBFF;
+// static const char32_t kUnicodeSurrogateLowStart = 0x0000DC00;
 static const char32_t kUnicodeSurrogateLowEnd     = 0x0000DFFF;
 static const char32_t kUnicodeSurrogateStart      = kUnicodeSurrogateHighStart;
 static const char32_t kUnicodeSurrogateEnd        = kUnicodeSurrogateLowEnd;