twrpTar: Fix uninitialized current_archive_type

* current_archive_type is not properly initialized
  leading to a potential random close(fd) in closeTar()

Change-Id: I1598ba4d524b723b8175ee847e2b1c5aeedbd938
diff --git a/twrpTar.cpp b/twrpTar.cpp
index d86e133..aa00044 100644
--- a/twrpTar.cpp
+++ b/twrpTar.cpp
@@ -1102,6 +1102,7 @@
 		}
 	} else {
 		// Not compressed or encrypted
+		current_archive_type = UNCOMPRESSED;
 		init_libtar_buffer(0, progress_pipe_fd);
 		if (part_settings->adbbackup) {
 			LOGINFO("Opening TW_ADB_BACKUP uncompressed stream\n");