webadmin: fixed header position in Hosts > Network subtab

PatternFly patch caused	the header to be badly positioned in Hosts >
Network Interfaces subtab, only in Firefox. It was a div clear issue.
Fixed.

Change-Id: I1db1830a203cb8c4ebb3b6d7c140676213506b35
Signed-off-by: Greg Sheremeta <gshereme@redhat.com>