webadmin: More accurate wording for IntegerValidation

The validation actually checks whether a number is lesser/greater than
OR equals minimum/maximum limits.

Change-Id: I553a53d40116c577cc97e43e3b6db2791bd0ab5e
Bug-Url: https://bugzilla.redhat.com/1115062
Signed-off-by: Lior Vernia <lvernia@redhat.com>