Rename data/staging to data/pkg_staging

Test: Build, flash, atest apex_e2e_tests
Change-Id: Ie66b0baaeb1845fdedbd6fa4bd5b33e63035627b
Fixes: 122999313
diff --git a/core/java/android/os/Environment.java b/core/java/android/os/Environment.java
index 3feccf5..0aed981 100644
--- a/core/java/android/os/Environment.java
+++ b/core/java/android/os/Environment.java
@@ -388,7 +388,7 @@
 
     /** {@hide} */
     public static File getDataStagingDirectory(String volumeUuid) {
-        return new File(getDataDirectory(volumeUuid), "staging");
+        return new File(getDataDirectory(volumeUuid), "pkg_staging");
     }
 
     /** {@hide} */