Verify that Talk could be enabled before executing the tests

This should make the problem clearer if Talk could not be enabled (for
example, due to a version mismatch), as otherwise the tests would fail
in more cryptic ways.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

build/integration/sharing_features/sharing-v1-video-verification.feature

@@ -4,6 +4,7 @@ Feature: sharing
     Given using api version "1"
     Given using old dav path
     Given invoking occ with "app:enable spreed"
+    Given the command was successful
 
   Scenario: Creating a link share with send password by Talk
     Given user "user0" exists