sbd: Wait for cluster to be up after corosync restart

Every time we start corosync, we need to wait for the cluster to be up.
And when we use sbd, we restart corosync to start sbd, so we need to
wait there too.
Fix installation of xfsprogs
Merge pull request #102 from vuntz/sbd-sync

sbd: Wait for cluster to be up after corosync restart
Merge pull request #103 from vuntz/install-xfs-fix

Fix installation of xfsprogs
fix interpolation of pid