Bind mount pkg specific dirs in the zygote child namespaces.

- Also update vold to create sandboxes for secondary storage devices.
- Since bind mounts are created in the process specific namespaces, we
  don't need /mnt/storage anymore which we were using it to prevent
  some bind mounts from propagating onto /mnt/runtime/write.
- Create bind mounts for {media,obb} dirs similar to data dir in
  per process namespace.
- Also fix a bug where we are not passing correct packages to vold when
  a new user starts.

Bug: 111890351
Test: manual
Change-Id: I7849efc4fbf3c654606fa30de7ab2de0236d766f
diff --git a/main.cpp b/main.cpp
index e1f8404..347c945 100644
--- a/main.cpp
+++ b/main.cpp
@@ -53,7 +53,7 @@
 
 int main(int argc, char** argv) {
     atrace_set_tracing_enabled(false);
-    setenv("ANDROID_LOG_TAGS", "*:d", 1);
+    setenv("ANDROID_LOG_TAGS", "*:d", 1);  // Do not submit with verbose logs enabled
     android::base::InitLogging(argv, android::base::LogdLogger(android::base::SYSTEM));
 
     LOG(INFO) << "Vold 3.0 (the awakening) firing up";