Eliminate test dependency on six for PY2 version check
Eliminate test dependency on six for PY2 version check

dpshelio/astropy-helpers,bsipocz/astropy-helpers,astropy/astropy-helpers,bsipocz/astropy-helpers,dpshelio/astropy-helpers,Cadair/astropy-helpers,Cadair/astropy-helpers,bsipocz/astropy-helpers,astropy/astropy-helpers