Mark tethering apex as compressible

Bug: 178713634
Test: presubmit
Change-Id: I621305e47b5b86408a72c622b1e367cd0e75f82c

Tethering/apex/Android.bp

@@ -34,6 +34,9 @@ apex {
     apps: ["Tethering"],
     manifest: "manifest.json",
     key: "com.android.tethering.key",
+    // Indicates that pre-installed version of this apex can be compressed.
+    // Whether it actually will be compressed is controlled on per-device basis.
+    compressible: true,
 
     androidManifest: "AndroidManifest.xml",
 }