lint: collapse merged exceptions

Python 3 has merged a number of exceptions into OSError.
Newer pylint warns when both are caught.

BUG=chromium:1006448
TEST=CQ passes

Change-Id: If401991269079d6bd7a358b387928a986c5ddc37
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2203763
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_uprev.py b/scripts/cros_uprev.py
index 6ecab4f..aeb14ab 100644
--- a/scripts/cros_uprev.py
+++ b/scripts/cros_uprev.py
@@ -266,7 +266,7 @@
     logging.error('An error occurred while uprevving %s: %s',
                   ebuild.package, e)
     raise
-  except (OSError, IOError):
+  except OSError:
     logging.warning(
         'Cannot rev %s\n'
         'Note you will have to go into %s '