BUILD: ssl_ckch: include ebpttree.h in ssl_ckch.c

It's used but is only found through other includes.
diff --git a/src/ssl_ckch.c b/src/ssl_ckch.c
index b9cddf2..2378ee3 100644
--- a/src/ssl_ckch.c
+++ b/src/ssl_ckch.c
@@ -22,6 +22,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include <import/ebpttree.h>
 #include <import/ebsttree.h>
 
 #include <haproxy/base64.h>