Cleanup uses of sprintf so we can deprecate it.

Change-Id: Ic66abfb547cd5551c47e03d604e65f83c84c597f
diff --git a/libs/androidfw/Asset.cpp b/libs/androidfw/Asset.cpp
index 4e14b13..2cfa666 100644
--- a/libs/androidfw/Asset.cpp
+++ b/libs/androidfw/Asset.cpp
@@ -69,7 +69,7 @@
             res.append(cur->getAssetSource());
             off64_t size = (cur->getLength()+512)/1024;
             char buf[64];
-            sprintf(buf, ": %dK\n", (int)size);
+            snprintf(buf, sizeof(buf), ": %dK\n", (int)size);
             res.append(buf);
         }
         cur = cur->mNext;