Bug#253621: [ef]grep check

[Clint Adams <schizo@debian.org>]

> What is the rationale behind this? Could you please explain that
> further?

Since nowadays egrep and fgrep are just shell scripts that run
'grep -E' or 'grep -F', running grep directly is always faster.

Furthermore, I believe that some people are working on POSIXifying base
for some embedded applications; grep -[EF] are mandated by POSIX,
[ef]grep are not.

This is not a major issue, but the only downside of adding it to lintian
would be potentially annoying people.