Change SAVE button in edit printer dialog to always be enabled

Previously, when a user provided an invalid PPD file the 'SAVE' button
in the edit printer dialog would be disabled. This would prevent users
from editing other fields in the dialog and saving the changes unless
the closed the dialog and reopened it again. Since there is already an
error message surfaced to the user indicating that the PPD they provided
is invalid, it should be okay to leave the button enabled.

BUG=chromium:830527
R=skau@chromium.org

Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Iec26a0c9473ce920f3337521ecaebfb8a2ffe5fe
Reviewed-on: https://chromium-review.googlesource.com/1028005Reviewed-by: Sean Kau <skau@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Dave Schuyler <dschuyler@chromium.org>
Commit-Queue: David Valleau <valleau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558093}

chrome/browser/resources/settings/printing_page/cups_edit_printer_dialog.html

@@ -116,8 +116,7 @@
             on-click="onCancelTap_">
           $i18n{cancel}
         </paper-button>
-        <paper-button class="action-button" on-click="onSaveTap_"
-            disabled="[[invalidPPD]]">
+        <paper-button class="action-button" on-click="onSaveTap_">
           $i18n{editPrinterButtonText}
         </paper-button>
       </div>