Reformat usage output in test_image.sh

[marcov]

Reformat the usage output displayed with help command or -h option.
Trap exit codes only after options parsing, as that is used to generate a test report.

Before:

Usage: test_images.sh [help|<distro>]                                                                                  
       test_images.sh [options]                                                                                        
                                                                                                                       
Options:                                                                                                               
                                                                                                                       
  -h | --help          # Show usage.                                                                                   
  --distro <distro>    # Only run tests for specified distro.                                                          
  --list               # List all distros that can be tested.                                                          
  --test-images-only   # Only run images tests for the list of distros under test.                                     
  --test-initrds-only  # Only run initrds tests for the list of distros under test.                                    
                                                                                                                       
Parameters:                                                                                                            
                                                                                                                       
                                                                                                                       
help     : Show usage.                                                                                                 
<distro> : Only run tests for specified distro.

Notes:

- If no options or parameters are specified, all tests will be run.                                                   

INFO: tests passed successfully - cleaning up

After:

Usage: test_images.sh [options] [command | <distro>]

Options:
  -h | --help          # Show usage.
  --distro <distro>    # Only run tests for specified distro.                                                         
  --list               # List all distros that can be tested.                                                         
  --test-images-only   # Only run images tests for the list of distros under test.                                    
  --test-initrds-only  # Only run initrds tests for the list of distros under test.                                   

Commands:
help     : Show usage.


When <distro> is specified, tests are run only for the specified <distro> distribution.                               
Otherwise, tests are be run on all distros.

[grahamwhaley]

lgtm

[grahamwhaley]

heh - will you be updating all scripts you touch? I think all our scripts are hard wired to /bin/bash - so, that could keep you busy for some time ;-)

[marcov]

That's not so bad if you just do that when stumbling on it :)
Btw I started to care about this when reviewing kata-containers/tests#692

[grahamwhaley]

hint - when changing the output of something like the help, it is useful to include the before and after example output in the merge or commit message - makes it easier to review ;-)

[marcov]

@grahamwhaley yep you are right:)