url: Fix conn reuse for local ports and interfaces

- Fix connection reuse for when the proposed new conn 'needle' has a
specified local port but does not have a specified device interface.

Bug: https://curl.haxx.se/mail/lib-2016-11/0137.html
Reported-by: bjt3[at]hotmail.com

1 files changed, 2 insertions, 3 deletions

diff --git a/lib/url.c b/lib/url.c
index 7106d46d4..552be9468 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -3400,9 +3400,8 @@ ConnectionExists(struct Curl_easy *data,
         */
         if((check->localport != needle->localport) ||
            (check->localportrange != needle->localportrange) ||
-           !check->localdev ||
-           !needle->localdev ||
-           strcmp(check->localdev, needle->localdev))
+           (needle->localdev &&
+            (!check->localdev || strcmp(check->localdev, needle->localdev))))
           continue;
       }