userportal: Check connect availability on doubleclick

This small patch adds checking whether user is allowed to connect to
console on doubleclick. (e.g. previously, when user doubleclicked vm
annoying dialog explaining that console isn't available would be
displayed).

Change-Id: I851b93eb8c68713be3c9738da551b59841623aa9
Signed-off-by: Frantisek Kobzik <fkobzik@redhat.com>