Rename product_services to system_ext

Bug: 134359158
Test: build and check if system_ext.img is created
Change-Id: I67f2e95dd29eac6a28e07e24ea973d3a134c3bfc
diff --git a/core/soong_config.mk b/core/soong_config.mk
index ac3cfb3..c32049d 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -146,7 +146,7 @@
 $(call add_json_str,  VendorPath,                        $(TARGET_COPY_OUT_VENDOR))
 $(call add_json_str,  OdmPath,                           $(TARGET_COPY_OUT_ODM))
 $(call add_json_str,  ProductPath,                       $(TARGET_COPY_OUT_PRODUCT))
-$(call add_json_str,  ProductServicesPath,               $(TARGET_COPY_OUT_PRODUCT_SERVICES))
+$(call add_json_str,  SystemExtPath,                     $(TARGET_COPY_OUT_SYSTEM_EXT))
 $(call add_json_bool, MinimizeJavaDebugInfo,             $(filter true,$(PRODUCT_MINIMIZE_JAVA_DEBUG_INFO)))
 
 $(call add_json_bool, UseGoma,                           $(filter-out false,$(USE_GOMA)))