Fix emailStrategy ListBox not displayed on MyPreferencesScreen

Commit 5d8f62c938bb9e1e7d493ffe56159cc3f82fd098 left out a "row++",
causing the "signed-off-by footer" CheckBox to replace the
emailStrategy ListBox instead of appearing on the next row.

The current preferences screen looks a bit messy. I'm reordering the
widgets in a follow-up change.

Change-Id: I7bff76be8262fa842e7bb4355b81b230cdb2742d
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/account/MyPreferencesScreen.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/account/MyPreferencesScreen.java
index f605abf..bcbdd6a 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/account/MyPreferencesScreen.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/account/MyPreferencesScreen.java
@@ -199,6 +199,7 @@
 
     formGrid.setText(row, labelIdx, Util.C.emailFieldLabel());
     formGrid.setWidget(row, fieldIdx, emailStrategy);
+    row++;
 
     formGrid.setText(row, labelIdx, "");
     formGrid.setWidget(row, fieldIdx, signedOffBy);