scripts: Remove -s option argument parsing that does not match

The -si and -sn arguments are handled in previous code branches.

scripts/Dpkg/Source/Package/V1.pm

@@ -369,9 +369,9 @@ sub do_build {
     if ($sourcestyle eq 'n') {
         $self->{options}{ARGV} = []; # ensure we have no error
         Dpkg::Source::Package::V3::Native::do_build($self, $dir);
-    } elsif ($sourcestyle =~ m/[nurUR]/) {
+    } elsif ($sourcestyle =~ m/[urUR]/) {
         if (stat($tarname)) {
-            unless ($sourcestyle =~ m/[nUR]/) {
+            unless ($sourcestyle =~ m/[UR]/) {
 		error(g_("tarfile '%s' already exists, not overwriting, " .
 		         'giving up; use -sU or -sR to override'), $tarname);
             }

scripts/dpkg-buildpackage.pl

@@ -244,7 +244,7 @@ while (@ARGV) {
 	@build_profiles = split /,/, $arg;
     } elsif (/^-s[iad]$/) {
 	push @changes_opts, $_;
-    } elsif (/^-(?:s[insAkurKUR]|[zZ].*|i.*|I.*)$/) {
+    } elsif (/^-(?:s[nsAkurKUR]|[zZ].*|i.*|I.*)$/) {
 	push @source_opts, $_; # passed to dpkg-source
     } elsif (/^-tc$/) {
 	$cleansource = 1;