workaround to fix screenshot leak on N4

Bug: 8322020

Change-Id: Ie60af0eb431866b8d64b2674ae7bd8b5ee05f5d6
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index f1e9c65..0ad471b 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2810,6 +2810,9 @@
 
     glDeleteTextures(1, &tname);
 
+    DisplayDevice::makeCurrent(mEGLDisplay,
+            getDefaultDisplayDevice(), mEGLContext);
+
     return result;
 }