Add some crowbar client nodes to /etc/hosts

For easier ssh matters
Add "intr" option for NFS mounts

Allows to abort hanging NFS calls (that otherwise wouldn't be
interruptible due to the "hard" default option).
Set NFS mount r/w operation default blocksize to 8k

Should obtain better performance.
Allow having "rw" NFS mounts.
Make sure nested=1 is set for kvm_intel

Won't hurt in the kvm_amd case. If kvm_intel is already running without
nested=1, remove it first before loading with nested=1 again.
Merge pull request #23 from saschpe/master-nestedvirtkvmintel

Make sure nested=1 is set for kvm_intel
Merge pull request #25 from saschpe/master-convenience

More stuff for NFS mounts and /etc/hosts
Get rid of "--slowset", we don't care
Skip changes generation when tar_scm does it already

Search for a tar_scm service that has a "changesgenerate" tag. Actually
it should check if it has the content "enabled", but that heavily
depends on the XPath capabilities of Perl, which I don't know.
mkcloud: make volume group name variable
mkcloud: make cloud name variable
mkcloud: dont setup nova_fixed network on host

this should be a cloud-internal network
mkcloud: drop explicit uuid

this is then randomly auto-assigned by libvirt
otherwise we would need to generate UUIDs for multiple clouds
mkcloud: allow virtual clouds with variable admin net
mkcloud: better cleanup network
mkcloud: use per-instance mountpoint
mkcloud: enable ksm on host

this can save multiple GB RAM
especially when running multiple clouds in parallel
Revert "Add some crowbar client nodes to /etc/hosts"

This reverts commit 0bc2a9eaef253708c20a6c6fedf237321c5f3100.

DNS aliases seem to be the better solution, check the discussion around
https://github.com/saschpe/automation/commit/0bc2a9eaef253708c20a6c6fedf237321c5f3100