[BUILD] Disable LOCALVERSION_AUTO in upstream Linux builds.

If this option is enabled then the Xen mercurial version ID gets
tacked onto the kernel version (e.g. 2.6.24-git22-hg2593b69b183b)
which is unlikely to be useful or desirable. All the trees which we
build using this method already have uniquely identifying versions
(e.g. 2.6.24-git22 or 2.6.24-mm1).

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

     1.1 --- a/buildconfigs/enable-xen-config	Tue Feb 12 14:59:01 2008 +0000
     1.2 +++ b/buildconfigs/enable-xen-config	Tue Feb 12 14:59:22 2008 +0000
     1.3 @@ -37,6 +37,7 @@ setopt CONFIG_XEN_BLKDEV_FRONTEND y
     1.4  setopt CONFIG_XEN_NETDEV_FRONTEND y
     1.5  setopt CONFIG_HVC_XEN y
     1.6  setopt CONFIG_NUMA n
     1.7 +setopt CONFIG_LOCALVERSION_AUTO n
     1.8  
     1.9  case ${XEN_TARGET_ARCH} in
    1.10      x86_32) setopt CONFIG_64BIT n ;;