Fix HNAS driver initialization

In iSCSI driver, when CHAP authentication is enabled, the driver would throw
an error message in the attempt to create the first volume after the driver
initialization. This is fixed by passing the right value to set_targetsecret.

Closes-Bug: #1402773
Change-Id: I554a67a2e19edb2e09c12febc339522719dfbe00
Merge "Fix HNAS driver initialization"