Description of problem:

When one creates (for whatever reason) more than one partition of type 'biosboot' or 'prepboot' in anaconda's manual partitioning, only the first instance is shown in a tree. The remaining partitions are not displayed in any tree, but they will be correctly created during install.

Version-Release number of selected component (if applicable):
anaconda 18.37.2

How reproducible:
always

Steps to Reproduce:

0. Boot F18-TC2
1. Enter STORAGE: INSTALLATION DESTINATION
2. Select the disk and do 'manual partitioning'
3. Delete all existing partitions
4. Create a 1mb biosboot partition
5. Create a 1mb biosboot partition AGAIN (it will not be shown).
6. Create a 1mb biosboot partition AGAIN (it will not be shown).
7. Create a / of 5gb
8. Press 'finish partitioning'
  
Note: For steps 4. to 6. one can use either a 1mb 'biosboot' or a 10mb 'prepboot' partition.

Actual results:
the partitions are created, but they are not shown in any tree during anaconda manual partitioning.

Expected results:
shown all partitions that will be created