Consistently use toLowerCase() in ConsoleUI.readEnum

The list of supported options was converting enum names to lower case
but the input prompt didn't do the same for the default value.

Change-Id: I9d300572dea830480362e92c91a8eae679d2f954
diff --git a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/init/api/ConsoleUI.java b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/init/api/ConsoleUI.java
index 18ccb1a..7f723b7 100644
--- a/gerrit-pgm/src/main/java/com/google/gerrit/pgm/init/api/ConsoleUI.java
+++ b/gerrit-pgm/src/main/java/com/google/gerrit/pgm/init/api/ConsoleUI.java
@@ -199,7 +199,7 @@
         T def, A options, String fmt, Object... args) {
       final String prompt = String.format(fmt, args);
       for (; ; ) {
-        String r = console.readLine("%-30s [%s/?]: ", prompt, def.toString());
+        String r = console.readLine("%-30s [%s/?]: ", prompt, def.toString().toLowerCase());
         if (r == null) {
           throw abort();
         }