Fix the "lingering close" problem when re-using a connection, as test case

160 shows.

We got no data and we attempted to re-use a connection. This might happen if
the connection was left alive when we were done using it before, but that was
closed when we wanted to read from it again. Bad luck. Retry the same request
on a fresh connect!

Deleted the sockerror variable again, it serves no purpose anymore.

lib/sendf.c

@@ -417,7 +417,6 @@ int Curl_read(struct connectdata *conn, /* connection data */
 
     if(-1 == nread) {
       int err = Curl_ourerrno();
-      conn->sockerror = err;
 #ifdef WIN32
       if(WSAEWOULDBLOCK == err)
 #else
@@ -425,8 +424,6 @@ int Curl_read(struct connectdata *conn, /* connection data */
 #endif
         return -1;
     }
-    else
-      conn->sockerror = 0; /* no error */
 
 #ifdef USE_SSLEAY
   }

lib/transfer.c

@@ -1946,15 +1946,14 @@ CURLcode Curl_perform(struct SessionHandle *data)
         res = Transfer(conn); /* now fetch that URL please */
         if(res == CURLE_OK) {
 
-          if((conn->keep.bytecount == 0) &&
-             (conn->sockerror == ECONNRESET) &&
+          if((conn->keep.bytecount+conn->headerbytecount == 0) &&
              conn->bits.reuse) {
-            /* We got no data, the connection was reset and we did attempt
-               to re-use a connection. This smells like we were too fast to
-               re-use a connection that was closed when we wanted to read
-               from it. Bad luck. Let's simulate a redirect to the same URL
-               to retry! */
-            infof(data, "Connection reset, retrying a fresh connect\n");
+            /* We got no data and we attempted to re-use a connection. This
+               might happen if the connection was left alive when we were done
+               using it before, but that was closed when we wanted to read
+               from it again. Bad luck. Retry the same request on a fresh
+               connect! */
+            infof(data, "Connection died, retrying a fresh connect\n");
             newurl = strdup(conn->data->change.url);
 
             conn->bits.close = TRUE; /* close this connection */

lib/urldata.h

@@ -577,8 +577,6 @@ struct connectdata {
                                single requests! */
   struct ntlmdata proxyntlm; /* NTLM data for proxy */
 
-  int sockerror; /* errno stored by Curl_read() if the underlying layer returns
-                    error */
   char syserr_buf [256]; /* buffer for Curl_strerror() */
 
 #if defined(USE_ARES) || defined(USE_THREADING_GETHOSTBYNAME)