Improve error message

The previous message indicated that the fault was due to an already-
connected window, which was misleading at times.

Bug 12439318

Change-Id: I1e0a042673dd245d1b0d237af963c52946803eb6
diff --git a/opengl/libs/EGL/eglApi.cpp b/opengl/libs/EGL/eglApi.cpp
index 0cc5265..b02ee0f 100644
--- a/opengl/libs/EGL/eglApi.cpp
+++ b/opengl/libs/EGL/eglApi.cpp
@@ -408,9 +408,11 @@
     if (dp) {
         EGLDisplay iDpy = dp->disp.dpy;
 
-        if (native_window_api_connect(window, NATIVE_WINDOW_API_EGL) != OK) {
-            ALOGE("EGLNativeWindowType %p already connected to another API",
-                    window);
+        int result = native_window_api_connect(window, NATIVE_WINDOW_API_EGL);
+        if (result != OK) {
+            ALOGE("eglCreateWindowSurface: native_window_api_connect (win=%p) "
+                    "failed (%#x) (already connected to another API?)",
+                    window, result);
             return setError(EGL_BAD_ALLOC, EGL_NO_SURFACE);
         }