Display correct version
Display correct version

`rally --version` displays correct version only on releases.
For release X+N patch, `rally --version` prints X+1 version, which is wrong(
since there is no X+1 release).

This patch changes displayed version to debian format:
 - <release_number> for releases
 - <last_release+1>~dev<number_of_patches_from_last_release> for development
   branch.

Change-Id: I53b1da26096172c0d7ccd275c9b3aff334bf569c

amit0701/rally,yeming233/rally,group-policy/rally,eayunstack/rally,gluke77/rally,eayunstack/rally,vganapath/rally,amit0701/rally,gluke77/rally,gluke77/rally,gluke77/rally,openstack/rally,vganapath/rally,vganapath/rally,amit0701/rally,openstack/rally,vganapath/rally,yeming233/rally,group-policy/rally,eayunstack/rally,eonpatapon/rally,openstack/rally,group-policy/rally,eonpatapon/rally,openstack/rally