Revert "Add proto flag "javanano_use_deprecated_package" to avoid build breakage"

This reverts commit cb767411.

Change-Id: I831abe3746be49fd164046655e8c5e059bae074f

protos/backup.proto

@@ -18,7 +18,6 @@ syntax = "proto2";
 
 package launcher_backup;
 
-option javanano_use_deprecated_package = true;
 option java_package = "com.android.launcher3.backup";
 option java_outer_classname = "BackupProtos";