BUILD: config: cfgparse-ssl.c needs tools.h

It calls parse_time_err() which is defined there but used to inherit it
through others.
diff --git a/src/cfgparse-ssl.c b/src/cfgparse-ssl.c
index 0a90da7..bf7bfc6 100644
--- a/src/cfgparse-ssl.c
+++ b/src/cfgparse-ssl.c
@@ -37,6 +37,7 @@
 #include <haproxy/listener.h>
 #include <haproxy/openssl-compat.h>
 #include <haproxy/ssl_sock.h>
+#include <haproxy/tools.h>
 
 
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