fix(http): fix panic when addrs in ConnectingTcpRemote is empty

Closes hyperium#2291

src/client/connect/http.rs

@@ -541,7 +541,13 @@ impl ConnectingTcpRemote {
             }
         }
 
-        Err(err.take().expect("missing connect error"))
+        match err {
+            Some(e) => Err(e),
+            None => Err(std::io::Error::new(
+                std::io::ErrorKind::NotConnected,
+                "Network unreachable"
+            ))
+        }
     }
 }