Fix pathtrace match for pipe2 syscall

* pathtrace.c (pathtrace_match): As pipe2 syscall has no descriptors
or paths to test, move SEN_pipe2 to the appropriate category.
diff --git a/pathtrace.c b/pathtrace.c
index e72cdf7..b2271c4 100644
--- a/pathtrace.c
+++ b/pathtrace.c
@@ -181,7 +181,6 @@
 	case SEN_name_to_handle_at:
 	case SEN_newfstatat:
 	case SEN_openat:
-	case SEN_pipe2:
 	case SEN_readlinkat:
 	case SEN_unlinkat:
 	case SEN_utimensat:
@@ -327,6 +326,7 @@
 	case SEN_memfd_create:
 	case SEN_perf_event_open:
 	case SEN_pipe:
+	case SEN_pipe2:
 	case SEN_printargs:
 	case SEN_socket:
 	case SEN_socketpair: