The logging functions are enhanced so that immediately prior to
the first log message being printed to any output channel, the
libvirt package version will be printed.

eg

 $ LIBVIRT_DEBUG=1 virsh
 18:13:28.013: 17536: info : libvirt version: 0.8.7
 18:13:28.013: 17536: debug : virInitialize:361 : register drivers
 ...

The 'configure' script gains two new arguments which can be
used as

   --with-packager="Fedora Project, x86-01.phx2.fedoraproject.org, 01-27-2011-18:00:10"
   --with-packager-version="1.fc14"

to allow distros to append a custom string with package specific
data.

The RPM specfile is modified so that it appends the RPM version,
the build host, the build date and the packager name.

eg

 $ LIBVIRT_DEBUG=1 virsh
 18:14:52.086: 17551: info : libvirt version: 0.8.7, package: 1.fc13 (Fedora Project, x86-01.phx2.fedoraproject.org, 01-27-2011-18:00:10)
 18:14:52.086: 17551: debug : virInitialize:361 : register drivers

Thus when distro packagers receive bug reports they can clearly
see what version was in use, even if the bug reporter mistakenly
or intentionally lies about version/builds

* src/util/logging.c: Output version data prior to first log message
* libvirt.spec.in: Include RPM release, date, hostname & packager
* configure.ac: Add --with-packager & --with-packager-version args