9.0-RC2 - bsdinstall miscount of remaining diskspace after partition deletion.

If you are performating a manual partion in 9.0-RC2 bsdinstall and 
you delete any created partition except the most recently created 
one, the total remaining space will be miscalculated.  Reproducable 
as shown below.

Workaround:  if you delete a partition that is not the last 
partition that was created, delete all partitions created after that 
partition before continuing.  Order does not seem to be important.

The results are similar with other hard drive sizes, with the i386 
or amd64 distributions, and with either 9.0-RC2 or 9.0-RC1 (I did 
not go back and check install discs prior to RC1)

Reproducing the miscount:

A 114 GB drive is used for this example:

   Select Manual Partitioning

   Perform the first Create on the drive and select GPT

   Creating the first partition:  "Add Partition" "size" shows 114GB

     Change size to 4GB, set mountpoint to  /  and tab to OK
       (agree to the boot partition creation)

   Create a second partition: "Add Partition" "size" shows 110GB

     Adjust size to 10GB, set mountpoint to  /usr and tab to OK

   Create a third partition: "Add Partition" "size" shows 100GB

     Adjust size to 20GB, set mountpoint to /var, and tab to OK

   Create a 4th partition: "size" shows 80GB remaining

     Adjust size to 40GB, set mountpoint to /data,  and tab to OK.

There is 40 GB remaining on the drive.  Now change the 
size of /var.  First, delete the currently configured /var 
partition.

In the Partition Editor, adding up all the lines on the screen shows 
54GB (plus a 64K boot) as allocated, so there should now be 60GB 
remaining.  But the deleted /var space has not been added back into 
the total.

Select Create again: "Add Partition" "size" shows 40GB

    Adjust size to 30GB, set mountpoint as /var, tab to OK

A subsequent "Create" will show that 20GB is remaining, rather than 
the actual remaining 30GB.  Selecting any size 20GB or larger for 
/home will give you a 20GB partition, and then an additional create 
will show the 10GB.