added a close for the local file descriptor (bug 137474)

* nanohttp.c: added a close for the local file descriptor
  (bug 137474)
diff --git a/nanohttp.c b/nanohttp.c
index 0bb5e77..7cd036f 100644
--- a/nanohttp.c
+++ b/nanohttp.c
@@ -1588,6 +1588,7 @@
     }
 
     xmlNanoHTTPClose(ctxt);
+    close(fd);
     return(0);
 }
 #endif /* LIBXML_OUTPUT_ENABLED */