Set apex_available property

The marked library(ies) were available to the APEXes via the
hand-written whitelist in build/soong/apex/apex.go. Trying to remove the
whitelist by adding apex_available property to the Android.bp of the
libraries.

Exempt-From-Owner-Approval: cherry-pick from AOSP

Bug: 150999716
Test: m
Merged-In: I274feb4542624b348999e7c5f189f8606c6cd63d
(cherry picked from commit 3144db91ba989f6744eba50e8897009a02bb26e3)
Change-Id: I274feb4542624b348999e7c5f189f8606c6cd63d
diff --git a/Android.bp b/Android.bp
index 44f3f03..d4afc1e 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,6 +1,10 @@
 cc_library_headers {
     name: "libnetd_client_headers",
     export_include_dirs: ["include"],
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.resolv",
+    ],
 }
 
 cc_defaults {