hardcode 'stable' to use stable-security mirror

mmdebstrap

@@ -3951,19 +3951,25 @@ sub get_sourceslist_by_suite {
         # the security mirror changes, starting with bullseye
         # https://lists.debian.org/87r26wqr2a.fsf@43-1.org
         my $bullseye_or_later = 0;
-        my $distro_info       = '/usr/share/distro-info/debian.csv';
+        if (
+            any { $_ eq $suite }
+            ('stable', 'bullseye', 'bookworm', 'trixie')
+        ) {
+            $bullseye_or_later = 1;
+        }
+        my $distro_info = '/usr/share/distro-info/debian.csv';
         # make $@ local, so we don't print "Can't locate Debian/DistroInfo.pm"
         # in other parts where we evaluate $@
         local $@ = '';
         eval { require Debian::DistroInfo; };
         if (!$@) {
-            # libdistro-info-perl is installed
+            debug "libdistro-info-perl is installed";
             my $debinfo = DebianDistroInfo->new();
             if ($debinfo->version($suite, 0) >= 11) {
                 $bullseye_or_later = 1;
             }
         } elsif (-f $distro_info) {
-            # distro-info-data is installed
+            debug "distro-info-data is installed";
             open my $fh, '<', $distro_info
               or error "cannot open $distro_info: $!";
             my $i = 0;
@@ -4010,13 +4016,7 @@ sub get_sourceslist_by_suite {
                 $bullseye_or_later = 1;
             }
         } else {
-            # neither libdistro-info-perl nor distro-info-data is installed
-            if (
-                any { $_ eq $suite }
-                ('stable', 'bullseye', 'bookworm', 'trixie')
-            ) {
-                $bullseye_or_later = 1;
-            }
+            debug "neither libdistro-info-perl nor distro-info-data installed";
         }
         if ($bullseye_or_later) {
             # starting from bullseye use