connect.c: Fixed compilation warning from commit 332e8d61

connect.c:952:5: warning: suggest explicit braces to avoid ambiguous 'else'

lib/connect.c

@@ -949,12 +949,13 @@ void Curl_sndbufset(curl_socket_t sockfd)
 
   static int detectOsState = DETECT_OS_NONE;
 
-  if(detectOsState == DETECT_OS_NONE)
+  if(detectOsState == DETECT_OS_NONE) {
     if(Curl_verify_windows_version(6, 0, PLATFORM_WINNT,
                                    VERSION_GREATER_THAN_EQUAL))
       detectOsState = DETECT_OS_VISTA_OR_LATER;
     else
       detectOsState = DETECT_OS_PREVISTA;
+  }
 
   if(detectOsState == DETECT_OS_VISTA_OR_LATER)
     return;