Description of problem:

Disabling the bootloader installation in manual partitioning and then using the partition creator assistant causes the storage configuration to be ejected in them main hub. The workaround is to do it all again. The fist time it does not work for some reason.

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

How reproducible:
always

Steps to Reproduce:
CASE#1:
0. Boot (no special boot parameters) with an UNLABELED disk (no partition table). (The partition table was zapped previously).
1. Enter STORAGE: INSTALLATION DESTINATION.
2. Select the disk. (Single drive guest).
3. Choose MANUAL PARTITIONING (Leave default LVM scheme).
4. Set 'do not install a bootloader'
5. Click the partition  creator assistant and let it propose the partitions.
6. Press 'finish partitioning'
7. MAIN HUB: STORAGE: "Error checking storage configuration"

CASE#2:
0. Boot (gpt kernel boot parameter) with an GPT labeled disk (but no partitions).
1. Enter STORAGE: INSTALLATION DESTINATION.
2. Select the disk. (Single drive guest).
3. Choose MANUAL PARTITIONING (Leave default LVM scheme).
4. Set 'do not install a bootloader'
5. Click the partition  creator assistant and let it propose the partitions.
6. Press 'finish partitioning'
7. MAIN HUB: STORAGE: "Error checking storage configuration"

CASE#3:
0. Boot (no special boot parameters) with an MSDOS labeled disk (but no partitions).
1. Enter STORAGE: INSTALLATION DESTINATION.
2. Select the disk. (Single drive guest).
3. Choose MANUAL PARTITIONING (Leave default LVM scheme).
4. Set 'do not install a bootloader'
5. Click the partition  creator assistant and let it propose the partitions.
6. Press 'finish partitioning'
7. MAIN HUB: STORAGE: "Error checking storage configuration"

For CASE#1,2,3 WORKAROUND:

8. Enter STORAGE: INSTALLATION DESTINATION (AGAIN)
9. Select the disk. (Single drive guest). (AGAIN)
10. Choose MANUAL PARTITIONING (Leave default LVM scheme). (AGAIN)
11. Verify that 'do not install a bootloader' is still set (IT IS)
12. The partitions will be already be there from previous try.
13. Press 'finish partitioning' and 'Begin Install'
14. The option 'do not install a bootloader' did work correctly, no
bootloader was installed.
  
Actual results:
one must retry the operation for the storage configuration to be accepted

Expected results:
no storage configuration rejection

Additional info:
once accepted, the option 'do not install bootloader' did work as expected.
Which means: no bootloader was installed.