BUG/MINOR: tcpcheck: Report hexstring instead of binary one on check failure

When an expect rule failed for a tcp-check, information about the expect
rule is dumped in the report. For a check on a binary string, a hexstring is
used in the configuration but the decoded string is dumped. It is an problem
because it can contain special characters. And it is not really handy
because there is no correspondance with the config.

So, now, the hexstring is dumped in the report. This way, we are sure there
is no special characters and it is easy to find it in the configuration.

This patch shoudl solve the issue #2326. It must be backported as far as
2.2.

(cherry picked from commit c72ab1cc6d8205152fb5accd929d4bd871871106)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/check.c b/src/check.c
index 7359c25..123a24e 100644
--- a/src/check.c
+++ b/src/check.c
@@ -860,7 +860,9 @@
 					chunk_appendf(chk, " (expect string '%.*s')", (unsigned int)istlen(expect->data), istptr(expect->data));
 					break;
 				case TCPCHK_EXPECT_BINARY:
-					chunk_appendf(chk, " (expect binary '%.*s')", (unsigned int)istlen(expect->data), istptr(expect->data));
+					chunk_appendf(chk, " (expect binary '");
+					dump_binary(chk, istptr(expect->data), (int)istlen(expect->data));
+					chunk_appendf(chk, "')");
 					break;
 				case TCPCHK_EXPECT_STRING_REGEX:
 					chunk_appendf(chk, " (expect regex)");