webadmin: fix typo in isDiscoveredHost entity

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1144807
Change-Id: I3e3a6e532bc61e7cd558ade549d0e1ccaa35900c
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>