Add a function to change disks to real
Add a function to change disks to real

Add a function recursively removing the forthcoming
flag of a list of disk objects. In this way, when disks
are committed, all parameters can be preserved.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Niklas Hambuechen <98215d3a72cb13cc9c9956528e50119ca7d1fb8b@google.com>

apyrgio/ganeti,andir/ganeti,bitemyapp/ganeti,mbakke/ganeti,apyrgio/ganeti,onponomarev/ganeti,dimara/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,mbakke/ganeti,leshchevds/ganeti,dimara/ganeti,grnet/snf-ganeti,grnet/snf-ganeti,yiannist/ganeti,ganeti/ganeti,bitemyapp/ganeti,leshchevds/ganeti,ganeti/ganeti,yiannist/ganeti,andir/ganeti,yiannist/ganeti,andir/ganeti,onponomarev/ganeti