fix apparent typo in fbcode_builder.py

Summary:
I noticed this while testing some changes; the comment
doesn't seem to match up to the `raise` statement, and attempting
to throw a list fails in python.

Reviewed By: strager

Differential Revision: D9566018

fbshipit-source-id: 563e43dfd30867993cc2a0f816db3b835a52e6df

build/fbcode_builder/fbcode_builder.py

@@ -238,7 +238,7 @@ class FBCodeBuilder(object):
         return self.step('Install packages for Debian-based OS', actions)
 
     def debian_ccache_setup_steps(self):
-        raise []  # It's ok to ship a renderer without ccache support.
+        return []  # It's ok to ship a renderer without ccache support.
 
     def github_project_workdir(self, project, path):
         # Only check out a non-default branch if requested. This especially