Fix incorrect exception handling in perfboot.py

RuntimeError used to be missed unintentionally.

BUG: 22207911
Change-Id: I69772350c22fac93d49745c3bc934dda7188bb77
diff --git a/init/perfboot.py b/init/perfboot.py
index 3d4940c..583d640 100755
--- a/init/perfboot.py
+++ b/init/perfboot.py
@@ -203,7 +203,7 @@
                 output_results(output, record_list, tags)
             if original_dropbox_max_files is not None:
                 restore_dropbox(device, original_dropbox_max_files)
-        except subprocess.CalledProcessError, RuntimeError:
+        except (subprocess.CalledProcessError, RuntimeError):
             pass
     atexit.register(cleanup)