Properly update iv_name of disks while changing templates
Properly update iv_name of disks while changing templates

Trasforming the disk of an instance from DRBD to plain did not properly
update the iv_name of disks, leaving it to None.

This commit modifies _ConvertDrbdToPlain to properly set the iv_name
variables.

An analogous fix is not required in the opposite function,
_ConvertPlainToDrbd, because it uses _GenerateDiskTemplate, that already
takes care of doing that.

Fixes Issue 403.

Signed-off-by: Michele Tartara <05f7077a2c6cbbdc4af4ba42e3ef89a0df846179@google.com>
Reviewed-by: Guido Trotter <f62ca4d5358bdaeef0e50e57f9f7e231de63727e@google.com>

ganeti-github-testing/ganeti-test-1,andir/ganeti,andir/ganeti,yiannist/ganeti,bitemyapp/ganeti,yiannist/ganeti,mbakke/ganeti,apyrgio/ganeti,mbakke/ganeti,leshchevds/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,yiannist/ganeti,apyrgio/snf-ganeti,grnet/snf-ganeti,grnet/snf-ganeti,apyrgio/snf-ganeti,leshchevds/ganeti,apyrgio/ganeti,dimara/ganeti,leshchevds/ganeti,ganeti/ganeti,onponomarev/ganeti,dimara/ganeti,mbakke/ganeti,ganeti/ganeti,andir/ganeti,ganeti/ganeti,onponomarev/ganeti