Fix warnings about unreferenced local variables.

BUG=angleproject:602

Change-Id: I2eb04fe6eed60b3877b14628e81c0b1fe3b68647
Reviewed-on: https://chromium-review.googlesource.com/193431
Tested-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
diff --git a/src/compiler/translator/ShaderLang.cpp b/src/compiler/translator/ShaderLang.cpp
index 5675f26..fe215b7 100644
--- a/src/compiler/translator/ShaderLang.cpp
+++ b/src/compiler/translator/ShaderLang.cpp
@@ -215,6 +215,7 @@
             // 64 bits hashing output requires 16 bytes for hex 
             // representation.
             const char HashedNamePrefix[] = HASHED_NAME_PREFIX;
+            (void)HashedNamePrefix;
             *params = 16 + sizeof(HashedNamePrefix);
         }
         break;