doc/articles/wiki: add missing log import to net/http tutorial

The log package is used with the net/http but was not in the import clause.

Change-Id: Ic45b987633adf0ee15defd4d136b5d37027e22b0
GitHub-Last-Rev: e74aff53370569864b7ec8c18617a5d992d34bf2
GitHub-Pull-Request: golang/go#36674
Reviewed-on: https://go-review.googlesource.com/c/go/+/215618
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
diff --git a/doc/articles/wiki/index.html b/doc/articles/wiki/index.html
index 4e3a5de..a74a58e 100644
--- a/doc/articles/wiki/index.html
+++ b/doc/articles/wiki/index.html
@@ -257,6 +257,7 @@
 import (
 	"fmt"
 	"io/ioutil"
+	"log"
 	<b>"net/http"</b>
 )
 </pre>