remove extraneous `using namespace android`

This namespace is not used by this file and its declaration is removed
in a separate CL from the only header that defines it, so remove this
extraneous line.

Test: Build
Change-Id: Ibec16b8889f4d886a9f9ec865d872e2437da034b
diff --git a/opengl/tests/gl_perf/filltest.cpp b/opengl/tests/gl_perf/filltest.cpp
index 3f8faca..4135c62 100644
--- a/opengl/tests/gl_perf/filltest.cpp
+++ b/opengl/tests/gl_perf/filltest.cpp
@@ -27,10 +27,6 @@
 #include <EGL/egl.h>
 #include <utils/Log.h>
 
-
-using namespace android;
-
-
 #include "fill_common.cpp"