Minor fixes

[friebel]

Connection logging after applying these changes:

> rshell --port /dev/cu.usbserial-01EDB820
Connecting to /dev/cu.usbserial-01EDB820 (buffer-size 32) ...
Trying to connect to REPL ... connected
Retrieving sysname ... esp32
Testing if ubinascii.unhexlify exists ... Y
Retrieving root directories ... /testdir/
Setting time ... Sep 25, 2022 09:45:09
Evaluating board_name ... pyboard
Retrieving time epoch ... Jan 01, 2000
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• Buffer size is not logged twice
• All operation ... result messages follow the same format
• Root directories list only includes directories, no files