MINOR: proto_http: replace generic opaque types by real used types in "http_capture"

This patch removes the generic opaque type for storing the configuration of the
action "http_capture"".
diff --git a/include/types/action.h b/include/types/action.h
index 188b17f..d3781cf 100644
--- a/include/types/action.h
+++ b/include/types/action.h
@@ -61,6 +61,10 @@
 			struct list logfmt;
 			int action;
 		} http;
+		struct {
+			struct sample_expr *expr;
+			struct cap_hdr *hdr;
+		} cap;
 		struct hlua_rule *hlua_rule;
 		struct {
 			struct sample_expr *expr;
diff --git a/src/proto_http.c b/src/proto_http.c
index 23c7eb4..f0ad1c2 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -12320,12 +12320,11 @@
                             struct session *sess, struct stream *s)
 {
 	struct sample *key;
-	struct sample_expr *expr = rule->arg.act.p[0];
-	struct cap_hdr *h = rule->arg.act.p[1];
+	struct cap_hdr *h = rule->arg.cap.hdr;
 	char **cap = s->req_cap;
 	int len;
 
-	key = sample_fetch_as_type(s->be, sess, s, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, expr, SMP_T_STR);
+	key = sample_fetch_as_type(s->be, sess, s, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->arg.cap.expr, SMP_T_STR);
 	if (!key)
 		return 1;
 
@@ -12471,8 +12470,8 @@
 
 		rule->action       = HTTP_REQ_ACT_CUSTOM_CONT;
 		rule->action_ptr   = http_action_req_capture;
-		rule->arg.act.p[0] = expr;
-		rule->arg.act.p[1] = hdr;
+		rule->arg.cap.expr = expr;
+		rule->arg.cap.hdr  = hdr;
 	}
 
 	else if (strcmp(args[cur_arg], "id") == 0) {