`mc find alias/bucket` without trailing slash is actually printing 'alias/bucket' as
first element in the output, the thing which is not taken into consideration in test_find
test. This commit will ask `mc find` to list 'alias/bucket/' instead to have a similar
output as gnu `ls` cmd.
Change the function name "fail" to "show_on_failure"
Add another function called "show_on_success" to handle certain
failure assert scenarios
Add missing Log success message for "test_config_host_add" and
"test_config_host_add_error" functions.
Fixes#2305
Previously `error` field is not populated properly due to double
formatting error message into JSON string. This patch fixes the issue
by avoid second time formatting in `printf` command.
Add new negative tests to functional tests. For that purpose, two functions are
introduced. assert_success makes sure that the passed command returns 0 exit code
and raise an error otherwise. assert_failure makes sure that the passed
command fails and raises an error otherwise.
