Log output to logcat

This makes it possible to run from an init script without losing the
output. There is no impact to the module scripts since the logcat output
is captured there anyway.

Signed-off-by: Andrew Gunnerson <accounts+github@chiller3.com>

app/src/main/java/com/chiller3/oemunlockonboot/Main.java

@@ -5,11 +5,14 @@
 import android.os.IInterface;
 import android.os.Process;
 import android.system.ErrnoException;
+import android.util.Log;
 
 import java.lang.reflect.Method;
 
 @SuppressLint({"DiscouragedPrivateApi", "PrivateApi", "SoonBlockedPrivateApi"})
 public class Main {
+    private static final String TAG = "OEMUnlockOnBoot";
+
     private static final int GET_SERVICE_ATTEMPTS = 30;
 
     @SuppressWarnings("SameParameterValue")
@@ -47,11 +50,11 @@ private static void unlock() throws Exception {
 
         Boolean unlockAllowed = (Boolean) isOemUnlockAllowedByUser.invoke(iFace);
         if (unlockAllowed) {
-            System.out.println("OEM unlocking already enabled");
+            Log.i(TAG, "OEM unlocking already enabled");
             return;
         }
 
-        System.out.println("Enabling OEM unlocking");
+        Log.i(TAG, "Enabling OEM unlocking");
         setOemUnlockAllowedByUser.invoke(iFace, true);
     }
 
@@ -77,8 +80,7 @@ public static void main(String[] args) {
             switchToSystemUid();
             unlock();
         } catch (Exception e) {
-            System.err.println("Failed to enable OEM unlocking");
-            e.printStackTrace();
+            Log.e(TAG, "Failed to enable OEM unlocking", e);
             System.exit(1);
         }
     }