Add virtmanager to the virt APEX

We want to have virtmanager (and its dependencies) inside the APEX so
that they can be updated. This library is a dependency of the binary,
therefore it should also be marked as being available to the APEX.

Bug: 180297657
Test: com.android.virt
Change-Id: I1886c2f07888fd2f22956a1ddf0081de3a54f458
diff --git a/Android.bp b/Android.bp
index bd99321..c023f5a 100644
--- a/Android.bp
+++ b/Android.bp
@@ -28,6 +28,10 @@
         // "--cfg std_atomic64", // not for arm/arm64
     ],
     proc_macros: ["libserde_derive"],
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.virt",
+    ],
 }
 
 // dependent_library ["feature_list"]