BLD: Don't include setup_requires since we'll complain earlier

if they're missing

Author: richafrank

setup.py

@@ -260,9 +260,10 @@ def setup_requirements(requirements_path, module_names, strict_bounds,
     conda_format=conda_build,
 )
 
-conditional_arguments = {
-    'setup_requires' if not conda_build else 'build_requires': setup_requires,
-}
+conditional_arguments = (
+    {'build_requires': setup_requires} if conda_build else {}
+)
+
 
 setup(
     name='zipline',