disk_setup: use byte string when purging the partition table (#2012)

This writes a byte string to the device instead of a string when
purging the partition table.

Essentially, this will prevent the error "a bytes-like object is
required, not 'str'" from happening.

1 files changed, 1 insertions, 1 deletions

diff --git a/cloudinit/config/cc_disk_setup.py b/cloudinit/config/cc_disk_setup.py
index 0248e7ec..4aae5530 100644
--- a/cloudinit/config/cc_disk_setup.py
+++ b/cloudinit/config/cc_disk_setup.py
@@ -657,7 +657,7 @@ def get_partition_gpt_layout(size, layout):
 def purge_disk_ptable(device):
     # wipe the first and last megabyte of a disk (or file)
     # gpt stores partition table both at front and at end.
-    null = "\0"
+    null = b"\0"
     start_len = 1024 * 1024
     end_len = 1024 * 1024
     with open(device, "rb+") as fp: