The `consul agent` command was ignoring extra command line arguments
which can lead to confusion when the user has for example forgotten to
add a dash in front of an argument or is not using an `=` when setting
boolean flags to `true`. `-bootstrap true` is not the same as
`-bootstrap=true`, for example.
Since all command line flags are known and we don't expect unparsed
arguments we can return an error. However, this may make it slightly
more difficult in the future if we ever wanted to have these kinds of
arguments.
Fixes#3397
24689c4f5e