Network config: Correctly select cr-input

Bug: 872905
Change-Id: I86cedf0cb9eedf8d32f7385eba3a3c85b42a35a8
Reviewed-on: https://chromium-review.googlesource.com/1176430Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583513}

ui/webui/resources/cr_components/chromeos/network/network_config.js

@@ -405,7 +405,7 @@ Polymer({
   focusFirstInput_: function() {
     Polymer.dom.flush();
     var e = this.$$(
-        'cr-input:not([disabled]),' +
+        'cr-input:not([readonly]),' +
         'network-password-input:not([disabled]),' +
         'network-config-select:not([disabled])');
     if (e)