ipatests: check for the "no sudo present" string absence

When sudo is installed, no warning should be output about sudo not
being available (obviously). Check that the relevant string is
not present.

Fixes: https://pagure.io/freeipa/issue/8530
Signed-off-by: François Cami <fcami@redhat.com>
Reviewed-By: Armando Neto <abiagion@redhat.com>

ipatests/test_integration/test_installation.py

@@ -1620,3 +1620,5 @@ class TestInstallWithoutSudo(IntegrationTest):
         tasks.install_packages(self.clients[0], ['sudo'])
         for pkg in ('sudo', 'libsss_sudo'):
             assert tasks.is_package_installed(self.clients[0], pkg)
+        result = tasks.install_client(self.master, self.clients[0])
+        assert self.no_sudo_str not in result.stderr_text