Move most of public/vold_prepare_subdirs.te to private

AIUI permissions should be in private unless they need to be public.

Bug: 25861755
Test: Boot device, create and remove a user, observe logs
Change-Id: I6c3521d50dab2d508fce4b614d51e163e7c8f3da

private/vold_prepare_subdirs.te

 domain_auto_trans(vold, vold_prepare_subdirs_exec, vold_prepare_subdirs)
 
+allow vold_prepare_subdirs system_file:file execute_no_trans;
+allow vold_prepare_subdirs shell_exec:file rx_file_perms;
+allow vold_prepare_subdirs toolbox_exec:file rx_file_perms;
+allow vold_prepare_subdirs devpts:chr_file rw_file_perms;
+allow vold_prepare_subdirs vold:fd use;
+allow vold_prepare_subdirs vold:fifo_file { read write };
+allow vold_prepare_subdirs file_contexts_file:file r_file_perms;
+allow vold_prepare_subdirs self:capability dac_override;
+allow vold_prepare_subdirs self:process setfscreate;
+allow vold_prepare_subdirs system_data_file:dir { open read write add_name remove_name };
+allow vold_prepare_subdirs vold_data_file:dir { create open read write search getattr setattr remove_name rmdir };
+allow vold_prepare_subdirs vold_data_file:file { getattr unlink };
 allow vold_prepare_subdirs storaged_data_file:dir create_dir_perms;

public/vold_prepare_subdirs.te

@@ -4,16 +4,3 @@ type vold_prepare_subdirs, domain;
 type vold_prepare_subdirs_exec, exec_type, file_type;
 
 typeattribute vold_prepare_subdirs coredomain;
-
-allow vold_prepare_subdirs system_file:file execute_no_trans;
-allow vold_prepare_subdirs shell_exec:file rx_file_perms;
-allow vold_prepare_subdirs toolbox_exec:file rx_file_perms;
-allow vold_prepare_subdirs devpts:chr_file rw_file_perms;
-allow vold_prepare_subdirs vold:fd use;
-allow vold_prepare_subdirs vold:fifo_file { read write };
-allow vold_prepare_subdirs file_contexts_file:file r_file_perms;
-allow vold_prepare_subdirs self:capability dac_override;
-allow vold_prepare_subdirs self:process setfscreate;
-allow vold_prepare_subdirs system_data_file:dir { open read write add_name remove_name };
-allow vold_prepare_subdirs vold_data_file:dir { create open read write search getattr setattr remove_name rmdir };
-allow vold_prepare_subdirs vold_data_file:file { getattr unlink };