Fixed the alpha blend mask not being initialized for masked clears.

TRAC #22590

Signed-off-by: Jamie Madill
Signed-off-by: Nicolas Capens
Author: Geoff Lang

git-svn-id: https://angleproject.googlecode.com/svn/branches/dx11proto@1917 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libGLESv2/renderer/Renderer11.cpp b/src/libGLESv2/renderer/Renderer11.cpp
index 7479294..15ae633 100644
--- a/src/libGLESv2/renderer/Renderer11.cpp
+++ b/src/libGLESv2/renderer/Renderer11.cpp
@@ -1588,7 +1588,7 @@
     glBlendState.colorMaskRed = (clearParams.mask & GL_COLOR_BUFFER_BIT) ? clearParams.colorMaskRed : false;
     glBlendState.colorMaskGreen = (clearParams.mask & GL_COLOR_BUFFER_BIT) ? clearParams.colorMaskGreen : false;
     glBlendState.colorMaskBlue = (clearParams.mask & GL_COLOR_BUFFER_BIT) ? clearParams.colorMaskBlue : false;
-    glBlendState.colorMaskBlue = (clearParams.mask & GL_COLOR_BUFFER_BIT) ? clearParams.colorMaskBlue : false;
+    glBlendState.colorMaskAlpha = (clearParams.mask & GL_COLOR_BUFFER_BIT) ? clearParams.colorMaskAlpha : false;
     glBlendState.sampleAlphaToCoverage = false;
     glBlendState.dither = false;