LVM: remove redundant casts to float

The vg_free_space field is always assigned a float, so additional casts
are not necessary.

Change-Id: Ic2af78ba7dbd7388cc071fc2f0ea876a1558d0e9
Merge "LVM: remove redundant casts to float"
(Test commit) Change README to reflect Jio's fork of Cinder

Change-Id: I3f26c0a736e63725aec24ca2fa12c707b8e6460f