Do not assume all requests are relocation requests
Do not assume all requests are relocation requests

Commit 717ede373 incorrectly assumed that each iallocator
request is about a specific instance and a specific disk
template. Both assumptions are wrong (consider e.g., a
node evacuation request) yielding a type error that,
unfortunately, in python is only discovered at run time.

Signed-off-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>
Reviewed-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>

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