git-credential-netrc: remove use of "autodie"

The "autodie" module was added in Perl 5.10.1, but our INSTALL
document says "version 5.8 or later is needed".

As discussed in <87efhfvxzu.fsf@evledraar.gmail.com> this script is in
contrib/, so we might not want to apply that policy, however in this
case "autodie" was recently added as a "gratuitous safeguard" in
786ef50a23 ("git-credential-netrc: accept gpg option",
2018-05-12) (see
<CAHqJXRE8OKSKcck1APHAHccLZhox+tZi8nNu2RA74RErX8s3Pg@mail.gmail.com>).

Looking at it more carefully the addition of "autodie" inadvertently
introduced a logic error, since having it is equivalent to this patch:

    @@ -245,10 +244,10 @@ sub load_netrc {
     	if ($gpgmode) {
     		my @cmd = ($options{'gpg'}, qw(--decrypt), $file);
     		log_verbose("Using GPG to open $file: [@cmd]");
    -		open $io, "-|", @cmd;
    +		open $io, "-|", @cmd or die "@cmd: $!";
     	} else {
     		log_verbose("Opening $file...");
    -		open $io, '<', $file;
    +		open $io, '<', $file or die "$file: $!$!;
     	}

     	# nothing to do if the open failed (we log the error later)

As shown in the context the intent of that code is not do die but to
log the error later.

Per my reading of the file this was the only thing autodie was doing
in this file (there was no other code it altered). So let's remove it,
both to fix the logic error and to get rid of the dependency.

1. <87efhfvxzu.fsf@evledraar.gmail.com>
   (https://public-inbox.org/git/87efhfvxzu.fsf@evledraar.gmail.com/)
2. <CAHqJXRE8OKSKcck1APHAHccLZhox+tZi8nNu2RA74RErX8s3Pg@mail.gmail.com>
   (https://public-inbox.org/git/CAHqJXRE8OKSKcck1APHAHccLZhox+tZi8nNu2RA74RErX8s3Pg@mail.gmail.com/)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/credential/netrc/git-credential-netrc

@@ -2,7 +2,6 @@
 
 use strict;
 use warnings;
-use autodie;
 
 use Getopt::Long;
 use File::Basename;