Before this change, the unix socket directory was hard-coded
to be e.g., /var/run/libvirt for euid==0 and ~/.libvirt otherwise.
With this change, you may now specify that directory in libvirtd's
config file via a line like this: unix_sock_dir = "/var/run/libvirt".
This is essential for running tests that do not impinge on any
existing libvirtd process, and in running tests in parallel.
* qemud/libvirtd.conf (unix_sock_dir): Add comment and example.
* qemud/qemud.h (struct qemud_server) [logDir]: Change type
from char[PATH_MAX] to char*.
* qemud/qemud.c (unix_sock_dir): New global
(remoteReadConfigFile): Set the global.
(qemudInitPaths): Use the global, unix_sock_dir, if non-NULL.
One minor improvement: unlink both sockets or none, never
just one of them.
(qemudCleanup): Free logDir.
(main): Use the new global rather than hard-coding "/run/libvirt".
* qemud/libvirtd.aug (sock_acl_entry): Add "unix_sock_dir".

* qemud/libvirtd.aug qemud/libvirtd.conf: document the new
  options in the config file and augment the Augeas description
daniel