webadmin: fix style misalignments in block domain view

Some alignment issues were introduced in block storage dialog and
DirectLUN disk dialog (lists/tabs/etc) - see attached screenshots in BZ.

Change-Id: I21975fb1fb5193322bf0e0d3565cc03767a4052c
Bug-Url: https://bugzilla.redhat.com/1133779
Signed-off-by: Daniel Erez <derez@redhat.com>