Coverity: Fix leaking UCharsetDetector in ftp code.

net/ftp/ftp_directory_listing_buffer.cc

Index: net/ftp/ftp_directory_listing_buffer.cc
diff --git a/net/ftp/ftp_directory_listing_buffer.cc b/net/ftp/ftp_directory_listing_buffer.cc
index 030da83d7cd4c145ce1c7f2fecf2166a60c86403..d7833e8cecf9d60e47e520d5f40e0d37624be2e2 100644
--- a/net/ftp/ftp_directory_listing_buffer.cc
+++ b/net/ftp/ftp_directory_listing_buffer.cc
@@ -27,6 +27,7 @@ std::string DetectEncoding(const std::string& text) {
                  &status);
   const UCharsetMatch* match = ucsdet_detect(detector, &status);
   const char* encoding = ucsdet_getName(match, &status);
+  ucsdet_close(detector);
   // Should we check the quality of the match? A rather arbitrary number is
   // assigned by ICU and it's hard to come up with a lower limit.
   if (U_FAILURE(status))