header_ok: Only keep first line of argument

This allows callers to pass the entire response without generating
overly long error messages.

ddclient.in

@@ -3774,6 +3774,7 @@ sub nic_updateable {
 ######################################################################
 sub header_ok {
     my ($host, $line) = @_;
+    $line =~ s/\r?\n.*//s;
     my $ok = 0;
 
     if ($line =~ m%^s*HTTP/.*\s+(\d+)%i) {

t/header_ok.pl

@@ -51,6 +51,12 @@ my @test_cases = (
         input => 'HTTP/1.1 456 bad',
         want => 0,
     },
+    {
+        desc => 'only first line is logged on error',
+        input => "HTTP/1.1 404 not found\n\nbody",
+        want => 0,
+        wantmsg => qr/(?!body)/,
+    },
 );
 
 for my $tc (@test_cases) {