Add snapuserd to VABC product and base_system.mk.

Bug: 168259959
Test: builds
Change-Id: I289f84e293c84b12f5f33f8940643bac43ff5d35
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 1a28cf0..a367232 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -248,6 +248,7 @@
     shell_and_utilities_system \
     sm \
     snapshotctl \
+    snapuserd \
     SoundPicker \
     storaged \
     surfaceflinger \