Avoid construct that only works in perl 5.20

--- caff/caff.orig	2015-04-27 21:19:22.000000000 +0200
+++ caff/caff	2015-04-27 21:19:28.000000000 +0200
@@ -714,7 +714,9 @@ sub readwrite_gpg($%) {
     # ignore direct and dup handles
     my @infhs  = grep {defined $opts{$_}      and !$handles->options($_)->{direct} and $handles->{$_} !~ /^[<>]&/} qw/stdin passphrase command/;
     my @outfhs = grep {defined $handles->{$_} and !$handles->options($_)->{direct} and $handles->{$_} !~ /^[<>]&/} qw/stdout stderr status logger/;
-    my %fh = reverse %$handles{@infhs, @outfhs};
+    my %fh;
+    $fh{$_} = $handles->{$_} foreach (@infhs, @outfhs);
+    %fh = reverse %fh;
 
     my %offset = map {$_ => 0}  @infhs;
     my %output = map {$_ => ''} @outfhs;
