BUG/MINOR: ring: Properly parse connect timeout

The connect timeout in a ring section was not properly parsed. Thus, it was
never set and the server timeout may be overwritten, depending on the
directives order. The first char of the keyword must be tested, not the
third one.

This patch is related to the issue #1900. But it does not fix the issue. It
must be backported as far as 2.4.
diff --git a/src/sink.c b/src/sink.c
index 29c3876..23cffc6 100644
--- a/src/sink.c
+++ b/src/sink.c
@@ -994,7 +994,7 @@
 				err_code |= ERR_ALERT | ERR_FATAL;
 				goto err;
 			}
-                        if (args[1][2] == 'c')
+                        if (args[1][0] == 'c')
                                 cfg_sink->forward_px->timeout.connect = tout;
                         else
                                 cfg_sink->forward_px->timeout.server = tout;