Make --verify-ssl choices explicit

[mfussenegger]

This adds true/false as explicit choices so that the help output is a
bit friendlier.

[--verify-ssl {True,False}]
--verify-ssl {True,False}
      Enable or disable the verification of the server SSL
      certificate

In CLIs with boolean flags it is also sometimes the case that you've a
--no-* variant or that you can use no or something like that. So
having to pass false is not necessarily intuitive.

[chaudum]

The --verify-ssl argument already supports yes/true/t/1/no/false/f/0 as input, but I agree, adding the choices makes the help text friendlier.

[mfussenegger]

Ah right, should we list all choices then? Or maybe go with ('true', 'false', 'yes', 'no') ?

[mfussenegger]

@chaudum pushed a fixup so that the error message is also friendlier if an invalid value is used:

crash --verify-ssl foobar
usage: crash [-h] [-v] [-A] [-a] [-U USERNAME] [-W] [--schema SCHEMA]
             [--history FILENAME] [--config FILENAME]
             [-c STATEMENT | --sysinfo] [--hosts [HOSTS [HOSTS ...]]]
             [--verify-ssl {true,false,yes,no}] [--cert-file FILENAME]
             [--key-file FILENAME] [--ca-cert-file FILENAME] [--format FORMAT]
             [--version]
crash: error: argument --verify-ssl: Input `foobar` cannot be converted to a boolean, expected one of: [yes, true, t, 1, no, false, f, 0]

[chaudum]

@chaudum pushed a fixup so that the error message is also friendlier if an invalid value is used:

crash --verify-ssl foobar
usage: crash [-h] [-v] [-A] [-a] [-U USERNAME] [-W] [--schema SCHEMA]
             [--history FILENAME] [--config FILENAME]
             [-c STATEMENT | --sysinfo] [--hosts [HOSTS [HOSTS ...]]]
             [--verify-ssl {true,false,yes,no}] [--cert-file FILENAME]
             [--key-file FILENAME] [--ca-cert-file FILENAME] [--format FORMAT]
             [--version]
crash: error: argument --verify-ssl: Input `foobar` cannot be converted to a boolean, expected one of: [yes, true, t, 1, no, false, f, 0]

Afaik the choices must the possible return values of the type function:

$ crash --verify-ssl true
usage: crash [-h] [-v] [-A] [-a] [-U USERNAME] [-W] [--schema SCHEMA]
             [--history FILENAME] [--config FILENAME]
             [-c STATEMENT | --sysinfo] [--hosts [HOSTS [HOSTS ...]]]
             [--verify-ssl {true,false,yes,no}] [--cert-file FILENAME]
             [--key-file FILENAME] [--ca-cert-file FILENAME] [--format FORMAT]
             [--version]
crash: error: argument --verify-ssl: invalid choice: True (choose from 'true', 'false', 'yes', 'no')