Send SIGINT once

This is enough (somehow) to abort rendering. With signal sent
twice Blender wil lsave crash report, which is not what we want.

benchmark/space/__init__.py

@@ -700,9 +700,6 @@ class BENCHMARK_OT_run(bpy.types.Operator):
                 self.progress_provider.process.kill()
             else:
                 import signal
-                # Corresponds to usual greeting of blender to hit Ctrl-C
-                # again to abort rendering.
-                self.progress_provider.process.send_signal(signal.SIGINT)
                 self.progress_provider.process.send_signal(signal.SIGINT)
 
     def cancel(self, context):