FYI 2.1.8 not deployed to maven central

[Josh Elser]

Looks like the 2.1.8 staging repository never got closed and released 
(no 2.1.8 in maven central).

I'm assuming that this is just an oversight? Looking at the archives, I 
see orgapachehbase-1378 is still closed (not released) which is the repo 
from the vote.

I'll get it published now.