Declare that testViewport targets Froyo APIs

(So that it can be built in Master, but run in
Froyo.)
diff --git a/opengl/tests/testViewport/Android.mk b/opengl/tests/testViewport/Android.mk
index 3da59b5..ab37809 100644
--- a/opengl/tests/testViewport/Android.mk
+++ b/opengl/tests/testViewport/Android.mk
@@ -17,6 +17,10 @@
 
 LOCAL_PACKAGE_NAME := TestViewport
 
+# Set a specific SDK version so we can run on Froyo.
+
+LOCAL_SDK_VERSION := 8
+
 include $(BUILD_PACKAGE)
 
 endif # TARGET_SIMULATOR