Replace MALLOC_IMPL with MALLOC_SVELTE.

Bug: http://b/26390299
Change-Id: Ib1bef4aa272033412bea57a9bccf1d67793d2bda
diff --git a/core/soong.mk b/core/soong.mk
index c464ba8..1d219c1 100644
--- a/core/soong.mk
+++ b/core/soong.mk
@@ -23,8 +23,8 @@
 	$(hide) mkdir -p $(dir $@)
 	$(hide) (\
 	echo '{'; \
-	echo '    "Device_uses_jemalloc": $(if $(filter dlmalloc,$(MALLOC_IMPL)),false,true),'; \
-	echo '    "Device_uses_dlmalloc": $(if $(filter dlmalloc,$(MALLOC_IMPL)),true,false),'; \
+	echo '    "Device_uses_jemalloc": $(if $(filter true,$(MALLOC_SVELTE)),false,true),'; \
+	echo '    "Device_uses_dlmalloc": $(if $(filter true,$(MALLOC_SVELTE)),true,false),'; \
 	echo '    $(if $(BOARD_MALLOC_ALIGNMENT),"Dlmalloc_alignment": $(BOARD_MALLOC_ALIGNMENT)$(comma),)'; \
 	echo '    "Platform_sdk_version": $(PLATFORM_SDK_VERSION),'; \
 	echo '    "Unbundled_build": $(if $(TARGET_BUILD_APPS),true,false),'; \