minorbug(mv): when -m is \x01 it do not quote it like gnu

[HackingRepo]

Hi, uutils mainteners

we confirmed uutils that not escape \x01 when using -m =, here is how to reproduce

relunsec@relunsec:~/software/coreutils/target/debug$ ./mkdir -m a=$'\x01' h/.
mkdir: invalid operator (expected +, -, or =, but found )
relunsec@relunsec:~/software/coreutils/target/debug$ gnumkdir -m a=$'\x01' h/.
gnumkdir: invalid mode ‘a=\001’
relunsec@relunsec:~/software/coreutils/target/debug$