RHEL7.2 installer always has unused PEs in LVM even if --grow option is specified in kickstart or auto partitioning in GUI is selected..

Issue

• RHEL7.2 installer always has unused PEs in LVM even if --grow option is specified in kickstart or auto partitioning in GUI is selected.

  Sample output:

  [root@localhost ~]# lvs
    LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
    root rhel -wi-ao---- 17.47g                                                    
    swap rhel -wi-ao----  2.00g                                                    
  [root@localhost ~]# vgdisplay
    --- Volume group ---
    VG Name               rhel
    System ID             
    Format                lvm2
    Metadata Areas        1
    Metadata Sequence No  3
    VG Access             read/write
    VG Status             resizable
    MAX LV                0
    Cur LV                2
    Open LV               2
    Max PV                0
    Cur PV                1
    Act PV                1
    VG Size               19.51 GiB
    PE Size               4.00 MiB
    Total PE              4994
    Alloc PE / Size       4984 / 19.47 GiB
    Free  PE / Size       10 / 40.00 MiB <-- HERE
  

  And the number of unused PEs is always 5 times of the count of existing LVs in VG.
  On the other hand, installer in RHEL7.3 or later doesn't cause this issue.