chimera: Fix creation time flag in ls command

The ls command of the chimera CLI fails to interpret the creation time
flag correctly.

Target: trunk
Request: 2.10
Request: 2.9
Require-notes: yes
Require-book: no
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Patch: https://rb.dcache.org/r/7268/
(cherry picked from commit 70d414e72c91b40fd914d9f069d17860643ba68f)
Merge pull request #821 from gbehrmann/fix/2.10/rb7268

chimera: Fix creation time flag in ls command