Minor logging fix for cmdmod._run

[DmitryKuzmenko]

What does this PR do?

This was detected when tests failed because of memory allocation errors.
In this case cmdmod reports "command not found" as an error reason when the original OSError says "cannot allocate memory".

What issues does this PR fix or reference?

Related to #53281

Previous Behavior

Error message on memory allocation failure looks like this:

Unable to run command '[u'grep', u'-lr', u'salt.utils.versions.warn_until', u'-A', u'1', u'/tmp/kitchen/testing/salt/']' with the context <CUT>, reason: command not found

New Behavior

Error message on memory allocation failure looks like this:

Unable to run command '[u'grep', u'-lr', u'salt.utils.versions.warn_until', u'-A', u'1', u'/tmp/kitchen/testing/salt/']' with the context <CUT>, reason: [Errno 12] Cannot allocate memory

Tests written?

Minor logging fix, tested manually.

Commits signed with GPG?

Yes

[DmitryKuzmenko]

Duplicates #49490