webadmin: fixed error icon position in dialog

Commit e9f27f4 caused the error icon to be off by a few pixels.
Fixed.

Change-Id: Ic4ebee8e86f6fdc840e5242a571b2cbc95c82dca
Bug-Url: https://bugzilla.redhat.com/1119027
Signed-off-by: Greg Sheremeta <gshereme@redhat.com>