Migrate to apex_manifest.pb

Fixing some references to apex_manifest.json.
apex_manifest.json is only for Q-compatibility.

Bug: 143951586
Test: m & flash & boot
Change-Id: I93b149d51b9b3f9b1f20e4a807c30555b6d53b7f
diff --git a/Android.mk b/Android.mk
index 2008c7f..6de27ae 100644
--- a/Android.mk
+++ b/Android.mk
@@ -377,7 +377,7 @@
 # regardless of which variant is installed, create a symlink so that
 # $(TARGET_OUT_UNSTRIPPED)/apex/com.android.art is linked to
 # $(TARGET_OUT_UNSTRIPPED)/apex/$(TARGET_ART_APEX).
-# Note that installation of the symlink is triggered by the apex_manifest.json
+# Note that installation of the symlink is triggered by the apex_manifest.pb
 # file which is the file that is guaranteed to be created regardless of the
 # value of TARGET_FLATTEN_APEX.
 #
@@ -388,9 +388,9 @@
 # directory so that the APEX is accessible via the canonical path
 # /apex/com.android.art
 ifeq ($(TARGET_FLATTEN_APEX),true)
-art_apex_manifest_file := $(PRODUCT_OUT)/system/apex/$(TARGET_ART_APEX)/apex_manifest.json
+art_apex_manifest_file := $(PRODUCT_OUT)/system/apex/$(TARGET_ART_APEX)/apex_manifest.pb
 else
-art_apex_manifest_file := $(PRODUCT_OUT)/apex/$(TARGET_ART_APEX)/apex_manifest.json
+art_apex_manifest_file := $(PRODUCT_OUT)/apex/$(TARGET_ART_APEX)/apex_manifest.pb
 endif
 
 art_apex_symlink_timestamp := $(call intermediates-dir-for,FAKE,com.android.art)/symlink.timestamp