Silence expected test error reports from the console output

The errors are still logged by common_test to the report it creates.
The process that is going to crash has to call cowboy_error_h:ignore/3
with the MFA where the crash is expected to occur for it to be ignored.
Gun retry failures are also ignored. Only unexpected crashes are printed.

test/cowboy_ct_hook.erl

@@ -0,0 +1,22 @@
+%% Copyright (c) 2014, Loïc Hoguin <essen@ninenines.eu>
+%%
+%% Permission to use, copy, modify, and/or distribute this software for any
+%% purpose with or without fee is hereby granted, provided that the above
+%% copyright notice and this permission notice appear in all copies.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+-module(cowboy_ct_hook).
+
+-export([init/2]).
+
+init(_, _) ->
+	error_logger:tty(false),
+	error_logger:add_report_handler(cowboy_error_h),
+	{ok, undefined}.