Fixes an issue with the build_sphinx test where it wasn't restoring the cwd correctly, and was also copying more of astropy_helpers than was necessary.
Fixes an issue with the build_sphinx test where it wasn't restoring the cwd correctly, and was also copying more of astropy_helpers than was necessary.

bsipocz/astropy-helpers,Cadair/astropy-helpers,embray/astropy_helpers,larrybradley/astropy-helpers,Cadair/astropy-helpers,astropy/astropy-helpers,bsipocz/astropy-helpers,embray/astropy_helpers,bsipocz/astropy-helpers,embray/astropy_helpers,dpshelio/astropy-helpers,dpshelio/astropy-helpers,larrybradley/astropy-helpers,astropy/astropy-helpers,embray/astropy_helpers,larrybradley/astropy-helpers