iotests: Add poke_file_[bl]e functions

Similarly to peek_file_[bl]e, we may want to write binary integers into
a file.  Currently, this often means messing around with poke_file and
raw binary strings.  I hope these functions make it a bit more
comfortable.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Code-suggested-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200324172757.1173824-3-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
1 file changed