Fix reference to uncleared variable in dex_preopt_odex_install.mk

dex_preopt_odex_install.mk referenced $(built_module), which is only
set by some prebuilt modules, leaving old values when building
non-prebuilt modules.  Use $(LOCAL_BUILT_MODULE) instead, which is set
for all modules by base_rules.mk.

Test: manual
Change-Id: Iecf092f9869d5edda3671d0999987906781d023e
diff --git a/core/dex_preopt_odex_install.mk b/core/dex_preopt_odex_install.mk
index a23bae2..d1c8fb2 100644
--- a/core/dex_preopt_odex_install.mk
+++ b/core/dex_preopt_odex_install.mk
@@ -266,7 +266,7 @@
 	  $(PRIVATE_DEXPREOPT_CONFIGS) \
 	  $(PRIVATE_RELAX_CHECK) \
 	  $<
-  $(built_module) : $(my_enforced_uses_libraries)
+  $(LOCAL_BUILT_MODULE) : $(my_enforced_uses_libraries)
 endif
 
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