Bug 18804: Skip selenium tests if Selenium::Remote::Driver is not installed

Bug 18804: Skip selenium tests if Selenium::Remote::Driver is not installed

We do not want these tests to fail if the module is not installed.
This module is not in the dependencies of Koha and it is good as it.
A developper who wants to use it will know what to do.
It is part of RM duties to make sure these tests pass

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Lee Jamison <ldjamison@marywood.edu>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
(cherry picked from commit 943a3a5c3ab4df6337607e1e237ff4f059d23da4)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>