installd: drop noatsecure for dex2oat

Ensure that AT_SECURE=1 is set when installd executes dex2oat.

LD_PRELOAD is no longer set by init, and installd couldn't see
LD_PRELOAD anyway due to https://android-review.googlesource.com/129971 .
Drop it.

Continuation of commit b00a0379

Change-Id: Icaf08768b3354c6a99dd0f77fef547a706cc96e9

installd.te

@@ -61,9 +61,6 @@ allow installd resourcecache_data_file:file create_file_perms;
 
 # Run dex2oat in its own sandbox.
 domain_auto_trans(installd, dex2oat_exec, dex2oat)
-# dex2oat needs LD_PRELOAD, passed down from init
-# https://android-review.googlesource.com/94851
-allow installd dex2oat:process noatsecure;
 
 # Upgrade from unlabeled userdata.
 # Just need enough to remove and/or relabel it.