webadmin: I18N - fix misalignment in import domain

Modify style of 'Activate Domain in Data Center' check-box
in import storage domain dialog (to fix misalignment
in French localization).

Change-Id: Ic489c119d4cf5fa4cc8f169d76442a0d8143ff53
Bug-Url: https://bugzilla.redhat.com/1123701
Bug-Url: https://bugzilla.redhat.com/1123702
Signed-off-by: Daniel Erez <derez@redhat.com>