Fix build warnings about unused private variables on clang

BUG=angle:638,677

Change-Id: Id9e80f0b86d9c24633b2d353a409844c22441d21
Reviewed-on: https://chromium-review.googlesource.com/203429
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Shannon Woods <shannonwoods@chromium.org>
diff --git a/src/compiler/translator/VersionGLSL.cpp b/src/compiler/translator/VersionGLSL.cpp
index dd11f99..3027a77 100644
--- a/src/compiler/translator/VersionGLSL.cpp
+++ b/src/compiler/translator/VersionGLSL.cpp
@@ -36,8 +36,7 @@
 //    - varying vec3 color; invariant color;
 //
 TVersionGLSL::TVersionGLSL(ShShaderType type)
-    : mShaderType(type),
-      mVersion(GLSL_VERSION_110)
+    : mVersion(GLSL_VERSION_110)
 {
 }