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, 7 insertions, 5 deletions

diff --git a/cloudinit/config/cc_power_state_change.py b/cloudinit/config/cc_power_state_change.py
index ab953a0d..6fcb8a7d 100644
--- a/cloudinit/config/cc_power_state_change.py
+++ b/cloudinit/config/cc_power_state_change.py
@@ -196,10 +196,11 @@ def load_power_state(cfg, distro_name):
 
     try:
         delay = convert_delay(delay, fmt=fmt, scale=scale)
-    except ValueError:
+    except ValueError as e:
         raise TypeError(
             "power_state[delay] must be 'now' or '+m' (minutes)."
-            " found '%s'." % delay)
+            " found '%s'." % delay
+        ) from e
 
     args = command + [delay]
     if message:
@@ -207,9 +208,10 @@ def load_power_state(cfg, distro_name):
 
     try:
         timeout = float(pstate.get('timeout', 30.0))
-    except ValueError:
-        raise ValueError("failed to convert timeout '%s' to float." %
-                         pstate['timeout'])
+    except ValueError as e:
+        raise ValueError(
+            "failed to convert timeout '%s' to float." % pstate['timeout']
+        ) from e
 
     condition = pstate.get("condition", True)
     if not isinstance(condition, (str, list, bool)):