Fix double free in FTP Code

* src/ftp.c(getftp): Don't free `target`. If it is not pointing to
  targetbuf, then it still pointing to its original location of u->dir.
  This location will be free'd later. Doing so now causes a double free
  and hence crashes Wget
* tests/Test-ftp-dir.px: New test to show double free error
* tests/Makefile.am: Add new test

src/ftp.c

@@ -992,9 +992,6 @@ Error in server response, closing control connection.\n"));
 
           /* 2004-09-20 SMS. */
 
-          if (target != targetbuf)
-            xfree (target);
-
         } /* else */
     }
   else /* do not CWD */

tests/Makefile.am

@@ -58,6 +58,7 @@ PX_TESTS = \
              Test-E-k-K.px \
              Test-E-k.px \
              Test-ftp.px \
+             Test-ftp-dir.px \
              Test-ftp-pasv-fail.px \
              Test-ftp-bad-list.px \
              Test-ftp-recursive.px \

tests/Test-ftp-dir.px

@@ -0,0 +1,44 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use FTPTest;
+
+
+###############################################################################
+
+my $afile = <<EOF;
+Some text.
+EOF
+
+$afile =~ s/\n/\r\n/;
+
+
+# code, msg, headers, content
+my %urls = (
+    '/dir/afile.txt' => {
+        content => $afile,
+    },
+);
+
+my $cmdline = $WgetTest::WGETPATH . " -S ftp://localhost:{{port}}//dir/afile.txt";
+
+my $expected_error_code = 0;
+
+my %expected_downloaded_files = (
+    'afile.txt' => {
+        content => $afile,
+    },
+);
+
+###############################################################################
+
+my $the_test = FTPTest->new (
+                             input => \%urls,
+                             cmdline => $cmdline,
+                             errcode => $expected_error_code,
+                             output => \%expected_downloaded_files);
+exit $the_test->run();
+
+# vim: et ts=4 sw=4