Reintroduce __version_info__ variable
Reintroduce __version_info__ variable

At least one application (mysql-workbench) (used to) use(s) the __version_info__
that got removed by commit 99859b8b021a5d13ca067a3e79560d6121f9c52f.

Breaking existing software with new versions of paramiko should be avoided.
This pull-request reintroduces the __version_info__ var, but fills it
from the __version__ var. No need to maintain multiple version strings.

Conflicts:
	paramiko/__init__.py

anadigi/paramiko,SebastianDeiss/paramiko,reaperhulk/paramiko,zpzgone/paramiko,mirrorcoder/paramiko,mhdaimi/paramiko,zarr12steven/paramiko,dorianpula/paramiko,redixin/paramiko,thusoy/paramiko,fvicente/paramiko,toby82/paramiko,Automatic/paramiko,jorik041/paramiko,alex/paramiko,torkil/paramiko,thisch/paramiko,selboo/paramiko,remram44/paramiko,varunarya10/paramiko,digitalquacks/paramiko,rcorrieri/paramiko,paramiko/paramiko,dlitz/paramiko,ameily/paramiko,davidbistolas/paramiko,CptLemming/paramiko,jaraco/paramiko,esc/paramiko