tox: bump the pylint version to 2.6.0 in the default run (#544)

Changes:

tox: bump the pylint version to 2.6.0 in the default run
Fix pylint 2.6.0 W0707 warnings (raise-missing-from)

1 files changed, 2 insertions, 1 deletions

diff --git a/cloudinit/subp.py b/cloudinit/subp.py
index 804ef3ca..3e4efa42 100644
--- a/cloudinit/subp.py
+++ b/cloudinit/subp.py
@@ -262,7 +262,8 @@ def subp(args, data=None, rcs=None, env=None, capture=True,
         raise ProcessExecutionError(
             cmd=args, reason=e, errno=e.errno,
             stdout="-" if decode else b"-",
-            stderr="-" if decode else b"-")
+            stderr="-" if decode else b"-"
+        ) from e
     finally:
         if devnull_fp:
             devnull_fp.close()