Update version numbers for the 1.2.3 release

Note: we don't update for now the install.sgml file with the new version
number, as there are no other changes. We'll update the web site to
indicate that the current install.html document is valid for 1.2.3 too.

Reviewed-by: imsnah,ultrotter

NEWS

+Version 1.2.3
+  - more tweaks to the disk activation code (especially helpful for DRBD)
+  - change the default ‘gnt-instance list’ output format, now there is
+    one combined status field (see the manpage for the exact values this
+    field will have)
+  - some more fixes for the mac export to hooks change
+  - make Ganeti not break with DRBD 8.2.x (which changed the version
+    format in /proc/drbd) (issue 24)
+  - add an upgrade tool from ‘remote_raid1’ disk template to ‘drbd’ disk
+    template, allowing migration from DRBD0.7+MD to DRBD8
+
 Version 1.2.2
   - fix ‘gnt-instance modify’ breakage introduced in 1.2.1 with the HVM
     support (issue 23)

configure.ac

 # Configure script for Ganeti
 AC_PREREQ(2.59)
-AC_INIT(ganeti, 1.2.2, ganeti@googlegroups.com)
+AC_INIT(ganeti, 1.2.3, ganeti@googlegroups.com)
 AC_CONFIG_AUX_DIR(autotools)
 AC_CONFIG_SRCDIR(configure)
 AM_INIT_AUTOMAKE([foreign tar-ustar])