Rename local currentDiskID to currentReleaseID
Rename local currentDiskID to currentReleaseID

because that's what it is.

Signed-off-by: Marco Voelz <46e670daac32cff840d1e50cdf9351c443be1923@sap.com>

allomov/bosh-init,cloudfoundry/bosh-init,allomov/bosh-init,cloudfoundry/bosh-init,allomov/bosh-init,forrestsill/bosh-init,forrestsill/bosh-init,cloudfoundry/bosh-init,forrestsill/bosh-init