cli: Indicate that session-timeout is in minutes

This patch modifies the CLI so that the documentation for the -S option
explicitly indicates that the unit is minutes.

Change-Id: I399879dadb29546be75d0f1a64dc1cc10c6917f0
Signed-off-by: Juan Hernandez <juan.hernandez@redhat.com>
(cherry picked from commit 0c7beaea28ece95dfd8a4e2b251473c6e820b34d)