Update lvm_vg_write() to handle the deferred commit of lvm_vg_write().

Update lvm_vg_write() to handle the deferred commit of lvm_vg_write().

Now that we've refactored the internal library functions that do the
vg_remove, we can handle the deferred commit of a lvm_vg_remove() inside
lvm_vg_write().  This makes the VG create/remove API more consistent in
terms of disk commits - they now both require an lvm_vg_write() to commit
the create or remove to disk.

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