migration: Guard ram_bytes_remaining against early call
Calling ram_bytes_remaining during the early part of setup is unsafe
because the ram_state isn't yet initialised.
This can happen in the sequence:
migrate
migrate_cancel
info migrate
if the migrate sticks trying to connect (e.g. to an unresponsive
destination due to the connect timeout). Here 'info migrate' sees
a state of CANCELLING and so assumes the migrate has partially happened.
partial fix for:
RH bz: https://bugzilla.redhat.com/show_bug.cgi?id=
1525899
Reported-by: Xianxian Wang <xianwang@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>