--quiet conflicts with HOMEBREW_VERBOSE for brew-outdated
=========================================================
I have `HOMEBREW_VERBOSE` set for many years, and it never conflicted with the `--quiet` flag on the command line. When `--quiet` is specified, it simply overrides `HOMEBREW_VERBOSE`, as is the convention for handling option vs environment variable in most *nix tools.
However, a few weeks ago, 867b155479be4a50e02580e05df770aec84438be (CC author @MikeMcQuaid) broke this. Now, using `--quiet` with `brew outdated` when `HOMEBREW_VERBOSE` is set simply results in an error saying `--quiet` and `--verbose` are mutually exclusive. (This broke my auto update script.) The problem apparently stems from making no distinction between `HOMEBREW_VERBOSE` and the `--verbose` option on the command line.
The point is: *command line option should override a conflicting env var when necessary, instead of being treated as a conflicting equal.*
# What you were trying to do (and why)
```console
$ HOMEBREW_VERBOSE=1 brew outdated --quiet
```
Why? Because I have `HOMEBREW_VERBOSE` set globally, and only override it on the command line as I see fit.
# What happened
```console
$ HOMEBREW_VERBOSE=1 brew outdated --quiet
Error: Options --quiet and --verbose are mutually exclusive.
```
# What you expected to happen
No error.
P.S. The help text doesn't help.
```console
$ brew outdated -h
Usage: brew outdated [options]
Show formulae that have an updated version available.
By default, version information is displayed in interactive shells, and
suppressed otherwise.
-q, --quiet List only the names of outdated brews
(takes precedence over --verbose).
```
Note *takes precedence over*.