Link to libsnapshot_cow and libz where libsnapshot is linked.

Bug: 168554689
Test: builds
Change-Id: Ibbb6b4795ee5f0056e52ad7379a0033092209e78
diff --git a/Android.bp b/Android.bp
index 27ba172..52019b6 100644
--- a/Android.bp
+++ b/Android.bp
@@ -203,6 +203,8 @@
         "libgsi",
         "libpayload_consumer",
         "libsnapshot",
+        "libsnapshot_cow",
+        "libz",
         "update_metadata-protos",
     ],
     shared_libs: [