Renaming SharedPreferences$Editor.startCommit to apply

Also removes the artifical restriction that only one apply() can be in
flight at once.  That was old from when I thought it'd end up being
required, but wasn't.

Change-Id: I3540ea8be6e0760d6a51d218186f71655c2f3f55
diff --git a/services/java/com/android/server/BootReceiver.java b/services/java/com/android/server/BootReceiver.java
index d15a058..b9ff8d0 100644
--- a/services/java/com/android/server/BootReceiver.java
+++ b/services/java/com/android/server/BootReceiver.java
@@ -167,7 +167,7 @@
             if (lastTime == fileTime) return;  // Already logged this particular file
             // TODO: move all these SharedPreferences Editor commits
             // outside this function to the end of logBootEvents
-            prefs.edit().putLong(filename, fileTime).startCommit();
+            prefs.edit().putLong(filename, fileTime).apply();
         }
 
         Slog.i(TAG, "Copying " + filename + " to DropBox (" + tag + ")");