Fix installing 2nd arch shared libraries

2ND_TARGET_DEPENDENCIES_ON_SHARED_LIBRARIES was not set,
which was causing the later += to act like = instead of
:=, and the dependencies would disappear as soon as
LOCAL_MODULE was cleared.

Change-Id: Idea291524fc06377deafec62f37d20eaa7f93bca
diff --git a/core/definitions.mk b/core/definitions.mk
index 7c29e30..b34e274 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -84,6 +84,7 @@
 # Target and host installed module's dependencies on shared libraries.
 # They are list of "<module_name>:<installed_file>:lib1,lib2...".
 TARGET_DEPENDENCIES_ON_SHARED_LIBRARIES :=
+2ND_TARGET_DEPENDENCIES_ON_SHARED_LIBRARIES :=
 HOST_DEPENDENCIES_ON_SHARED_LIBRARIES :=
 
 # Generated class file names for Android resource.