Discard framebuffer commands when we redraw the entire buffer

Change-Id: I32e3014832cbd3bdbace8c3d2206eb20a2002d64
diff --git a/libs/hwui/LayerRenderer.cpp b/libs/hwui/LayerRenderer.cpp
index 5a8f2b7..02af5e2 100644
--- a/libs/hwui/LayerRenderer.cpp
+++ b/libs/hwui/LayerRenderer.cpp
@@ -332,10 +332,10 @@
         if (Caches::getInstance().extensions.hasDiscardFramebuffer()) {
             GLuint previousFbo;
             glGetIntegerv(GL_FRAMEBUFFER_BINDING, (GLint*) &previousFbo);
-
-            GLenum attachments = GL_COLOR_ATTACHMENT0;
             if (fbo != previousFbo) glBindFramebuffer(GL_FRAMEBUFFER, fbo);
-            glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, &attachments);
+
+            const GLenum attachments[] = { GL_COLOR_ATTACHMENT0 };
+            glDiscardFramebufferEXT(GL_FRAMEBUFFER, 1, attachments);
 
             if (fbo != previousFbo) glBindFramebuffer(GL_FRAMEBUFFER, previousFbo);
         }