webadmin: fix NPE in WebAdminHostPageServletTest

Two @Before methods in WebAdminHostPageServletTest is causing the tests
to fail with NPE on my laptop. Merging them into single one resolves the
problem.

Change-Id: Ib76f7bd842d3b58c522e3e97609a9b55d5a79902
Signed-off-by: Shireesh Anjal <sanjal@redhat.com>