Fix 2nd arch prefix application

Bug: 17887283
Change-Id: I7b3b2332212fe416d6b5f5c2e5c1e07605ba09aa
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index 0cff660..ad2db0d 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -98,10 +98,10 @@
 # Library used by dlext tests - zipped and aligned
 # -----------------------------------------------------------------------------
 include $(CLEAR_VARS)
-bionic_2nd_arch_prefix := $(TARGET_2ND_ARCH_VAR_PREFIX)
+bionic_2nd_arch_prefix :=
 include $(LOCAL_PATH)/Android.build.dlext_testzip.mk
 ifneq ($(TARGET_2ND_ARCH),)
-  bionic_2nd_arch_prefix :=
+  bionic_2nd_arch_prefix := $(TARGET_2ND_ARCH_VAR_PREFIX)
   include $(LOCAL_PATH)/Android.build.dlext_testzip.mk
 endif