declare dir for non data/media devices

Change-Id: I60e2e2a880c3bd5fff3f485f7c8e4ac9ab6fd3bd
diff --git a/twrpTar.cpp b/twrpTar.cpp
index 48d529b..e77e1d0 100644
--- a/twrpTar.cpp
+++ b/twrpTar.cpp
@@ -714,6 +714,8 @@
 			string dir(tardir + "/" + de->d_name);
 		    skip_dir = du.check_skip_dirs(dir);
 			if (skip_dir) continue;
+#else
+			string dir;
 #endif
 			dir = de->d_name;
 		    skip_dir = du.check_skip_dirs(dir);