fix getting and setting contexts in selinux

recreate lost+found with selinux contexts

Change-Id: I19e8696d47319dfb641520956c8a27c2a796a0c3
diff --git a/twrp.cpp b/twrp.cpp
index 765cad3..56ffedb 100644
--- a/twrp.cpp
+++ b/twrp.cpp
@@ -104,10 +104,18 @@
 	gui_loadResources();
 
 #ifdef HAVE_SELINUX
+	if (TWFunc::Path_Exists("/prebuilt_file_contexts")) {
+		if (TWFunc::Path_Exists("/file_contexts")) {
+			printf("Renaming regular /file_contexts -> /file_contexts.bak\n");
+			rename("/file_contexts", "/file_contexts.bak");
+		}
+		printf("Moving /prebuilt_file_contexts -> /file_contexts\n");
+		rename("/prebuilt_file_contexts", "/file_contexts");
+	}
 	struct selinux_opt selinux_options[] = {
 		{ SELABEL_OPT_PATH, "/file_contexts" }
 	};
-    selinux_handle = selabel_open(SELABEL_CTX_FILE, selinux_options, 1);
+	selinux_handle = selabel_open(SELABEL_CTX_FILE, selinux_options, 1);
 	if (!selinux_handle)
 		printf("No file contexts for SELinux\n");
 	else