build: set version based on git tag or specific

This patch brings version and release number generated at build time
using git tags or fixed content from VERSION file.

With git tag, version/release number are got from output of
'git describe --tags --match "v[0-9]*"' command.

This behavior can be overriden by having VERSION file with fixed
version/release.  The VERSION file should have text describing version
and release for example something like 'v3.4.0-1'

For testing this patch, its required to remove autom4te.cache
directory to avoid seeing previously set version.

BUG: 1074919
Change-Id: I8f68172e8b389b0ba0846e9adb4b597e67a909aa
Signed-off-by: Bala.FA <barumuga@redhat.com>
Reviewed-on: http://review.gluster.org/7164
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>