Fix YesNoPrompt API to be saner.

BUG=None
TEST=unittests.

Change-Id: If06e50f6f73a890efd54d0ce12c3099e5e37083b
Reviewed-on: https://gerrit.chromium.org/gerrit/37163
Reviewed-by: Brian Harring <ferringb@chromium.org>
Tested-by: Brian Harring <ferringb@chromium.org>
Commit-Ready: Brian Harring <ferringb@chromium.org>
diff --git a/scripts/deploy_chrome.py b/scripts/deploy_chrome.py
index f5a5c08..e87ed84 100644
--- a/scripts/deploy_chrome.py
+++ b/scripts/deploy_chrome.py
@@ -143,9 +143,7 @@
                    'verification, which requires that it reboot the device.')
       logging.info('Make sure the device is in developer mode!')
       logging.info('Skip this prompt by specifying --force.')
-      result = cros_build_lib.YesNoPrompt(
-          'no', prompt='Remove roots verification?')
-      if result == 'no':
+      if not cros_build_lib.BooleanPrompt('Remove roots verification?', False):
         cros_build_lib.Die('Need rootfs verification to be disabled. '
                            'Aborting.')