Derive fingerprint at runtime when undefined.

Some devices leave "ro.build.fingerprint" undefined at build time,
since they need to build it from the components at runtime.

Bug: 13340779
Change-Id: I4d74398817af22079a11c196dc6742b85d2bfb61

services/java/com/android/server/SystemServer.java

@@ -29,6 +29,7 @@ import android.content.pm.IPackageManager;
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
 import android.media.AudioService;
+import android.os.Build;
 import android.os.Environment;
 import android.os.FactoryTest;
 import android.os.Handler;
@@ -201,6 +202,10 @@ public final class SystemServer {
         // as efficient as possible with its memory usage.
         VMRuntime.getRuntime().setTargetHeapUtilization(0.8f);
 
+        // Some devices rely on runtime fingerprint generation, so make sure
+        // we've defined it before booting further.
+        Build.ensureFingerprintProperty();
+
         // Within the system server, it is an error to access Environment paths without
         // explicitly specifying a user.
         Environment.setUserRequired(true);