use printwriter instead of stdout

stdout doesn't make it to 'adb', so, "adb install-multiple" claims to fail
even though it successfully commits the install

Change-Id: I4df8cfc134a2d6c06cca13c2fc49a5cc7a07cc4a

services/core/java/com/android/server/pm/PackageManagerShellCommand.java

@@ -1236,7 +1236,7 @@ class PackageManagerShellCommand extends ShellCommand {
                     PackageInstaller.STATUS_FAILURE);
             if (status == PackageInstaller.STATUS_SUCCESS) {
                 if (logSuccess) {
-                    System.out.println("Success");
+                    pw.println("Success");
                 }
             } else {
                 pw.println("Failure ["