libpfctl: add pfctl_get_rule_h()

Add a handle variant of pfctl_get_rule(). This converts us from using
the nvlist variant to the netlink variant, and also moves us closer to a
world where all libpfctl functions take the handle.

While here have pfctl use the new function.

Sponsored by:	Rubicon Communications, LLC ("Netgate")

lib/libpfctl/libpfctl.c

@@ -1388,6 +1388,14 @@ pfctl_get_rules_info(int dev __unused, struct pfctl_rules_info *rules, uint32_t
 	return (error);
 }
 
+int
+pfctl_get_rule_h(struct pfctl_handle *h, uint32_t nr, uint32_t ticket, const char *anchor,
+    uint32_t ruleset, struct pfctl_rule *rule, char *anchor_call)
+{
+	return (pfctl_get_clear_rule_h(h, nr, ticket, anchor, ruleset, rule,
+	    anchor_call, false));
+}
+
 int
 pfctl_get_rule(int dev, uint32_t nr, uint32_t ticket, const char *anchor,
     uint32_t ruleset, struct pfctl_rule *rule, char *anchor_call)

lib/libpfctl/libpfctl.h

@@ -420,6 +420,9 @@ int	pfctl_get_rules_info(int dev, struct pfctl_rules_info *rules,
 int	pfctl_get_rule(int dev, uint32_t nr, uint32_t ticket,
 	    const char *anchor, uint32_t ruleset, struct pfctl_rule *rule,
 	    char *anchor_call);
+int	pfctl_get_rule_h(struct pfctl_handle *h, uint32_t nr, uint32_t ticket,
+	    const char *anchor, uint32_t ruleset, struct pfctl_rule *rule,
+	    char *anchor_call);
 int	pfctl_get_clear_rule(int dev, uint32_t nr, uint32_t ticket,
 	    const char *anchor, uint32_t ruleset, struct pfctl_rule *rule,
 	    char *anchor_call, bool clear);