webclient: Fix errno in case of recv failure

When recv() failed, the current code assumes the return value
of recv() is a negative errno. It's wrong. Actually the return value
in case of error is -1. The wrong assumption ends up with reporting
EPERM, as EPERM happens to be -(-1).

This commit changes the code to leave the errno set by the failed
recv() as it is. It should be fine as wget_base() has the same
error returning convention as recv(). That is, return -1 (ERROR)
and set errno in the case of failure.

NOTE: the close() after the errout label can also fail and overwrite
the errno. I don't feel it's a big problem as wget_base() doesn't have
any promise about which error should be reported.

netutils/webclient/webclient.c

@@ -678,8 +678,7 @@ static int wget_base(FAR const char *url, FAR char *buffer, int buflen,
           if (ws->datend < 0)
             {
               nerr("ERROR: recv failed: %d\n", errno);
-              ret = ws->datend;
-              goto errout_with_errno;
+              goto errout;
             }
           else if (ws->datend == 0)
             {