vz: fix disk enumeration

If we want to delete all disks for container or vm
we should make a loop from 0 to NumberOfDisks and always
use zero index in PrlVmCfg_GetHardDisk to get disk handle.
When we delete first disk after that numbers of other disks
will be changed, start from 0 to NumberOfDisks-1.
That's why we should always use zero index.

src/vz/vz_sdk.c

@@ -3810,7 +3810,7 @@ prlsdkDetachDomainHardDisks(PRL_HANDLE sdkdom)
     prlsdkCheckRetGoto(pret, cleanup);
 
     for (i = 0; i < hddCount; ++i) {
-        pret = PrlVmCfg_GetHardDisk(sdkdom, i, &sdkdisk);
+        pret = PrlVmCfg_GetHardDisk(sdkdom, 0, &sdkdisk);
         prlsdkCheckRetGoto(pret, cleanup);
 
         pret = PrlVmDev_Remove(sdkdisk);