brew: error out if bad xcode-select path given

Since a bad xcode-select path can cause many brew commands to freeze,
it's worth warning users and bailing out as early as possible.

The doctor check wasn't good enough, since the doctor could freeze
before the warning about this was ever printed.
Adjust bad xcode-select path exit code
qt5 5.2.0

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
qt5: update 5.2.0 bottle.

Closes #25165.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>