fix a crasher in our EGL wrapper when attrib_list is NULL in eglChooseConfig

the EGL specification states that this should be treated as though it was
an empty list terminated with EGL_NONE.

Change-Id: I294104370a86b5e5c34c7bcf15c5459eab464631
diff --git a/opengl/libs/EGL/egl.cpp b/opengl/libs/EGL/egl.cpp
index e6cf792..ba09d08 100644
--- a/opengl/libs/EGL/egl.cpp
+++ b/opengl/libs/EGL/egl.cpp
@@ -843,10 +843,12 @@
     EGLint patch_index = -1;
     GLint attr;
     size_t size = 0;
-    while ((attr=attrib_list[size]) != EGL_NONE) {
-        if (attr == EGL_CONFIG_ID)
-            patch_index = size;
-        size += 2;
+    if (attrib_list) {
+        while ((attr=attrib_list[size]) != EGL_NONE) {
+            if (attr == EGL_CONFIG_ID)
+                patch_index = size;
+            size += 2;
+        }
     }
     if (patch_index >= 0) {
         size += 2; // we need copy the sentinel as well