rgw: remove suggestion to upgrade libcurl

Reported-by: Ken Dreyer <kdreyer@redhat.com>
Signed-off-by: Casey Bodley <cbodley@redhat.com>
(cherry picked from commit dcff120)

src/rgw/rgw_http_client.cc

@@ -399,8 +399,7 @@ static int detect_curl_multi_wait_bug(CephContext *cct, CURLM *handle,
     curl_multi_wait_bug_present = true;
     ldout(cct, 0) << "WARNING: detected a version of libcurl which contains a "
         "bug in curl_multi_wait(). enabling a workaround that may degrade "
-        "performance slightly. please upgrade to a more recent version of "
-        "libcurl." << dendl;
+        "performance slightly." << dendl;
   }
 
   return clear_signal(read_fd);