Rename RollbackInfo.getSessionId to getCommittedSessionId.

To clarify which session id it is returning.

Bug: 112431924
Test: builds.
Change-Id: I991477636f21440894d595f93926a32b7380708b
diff --git a/core/java/android/content/rollback/RollbackInfo.java b/core/java/android/content/rollback/RollbackInfo.java
index 1111b43..3fd2476 100644
--- a/core/java/android/content/rollback/RollbackInfo.java
+++ b/core/java/android/content/rollback/RollbackInfo.java
@@ -83,7 +83,7 @@
      * Returns the session ID for the committed rollback for staged rollbacks.
      * Only applicable for rollbacks that have been committed.
      */
-    public int getSessionId() {
+    public int getCommittedSessionId() {
         // TODO: Support rollback of staged installs.
         return PackageInstaller.SessionInfo.INVALID_ID;
     }