Bug#842549: haskell-devscripts: Dh_Haskell.sh should respect DH_VERBOSE settings

[Felix Lechner]

Hi,

> Dh_Haskell.sh doesn't respect the DH_VERBOSE settings

Dh_Haskell.sh cannot do that very well—at least not with respect to
suppressing output—because callers of the shell functions rely on
information in stdout for results. (The functions also reuse each
other.)

In a potential step forward, however, I wrote a Perl module that will
soon sidestep Dh_Haskell.sh when builds are started from dh-haskell's
dh sequencer. That Perl module will honor DH_VERBOSE.

A merge request is in the works and will be submitted when testing is complete.

Kind regards,
Felix Lechner