Remove extraneous messages for extent_size and alloc_policy upon vgcreate.

Remove extraneous messages for extent_size and alloc_policy upon vgcreate.

When converting to the new liblvm functions, the vgcreate code path
changed to create a new vg, then set values.  As a result of this
change, and the fact that we give a user a message if they try to
set the same value of a VG attribute (extent_size, alloc_policy, etc),
you'll see these 2 extraneous "is already" messages with vgcreate:
tools/lvm vgcreate vg2 /dev/loop2
  Physical extent size of VG vg2 is already 4.00 MB
  Volume group allocation policy is already normal
  Volume group "vg2" successfully created

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Author: Dave Wysochanski <dwysocha@redhat.com>