Fix directory move into itself and prevent more fs changes when read-only

[tannewt]

No description provided.

[tannewt]

Here is the code I tested with:

import os
try:
    os.rmdir("/tmp/bar")
except OSError:
    pass
try:
    os.rmdir("/tmp/barfoo")
except OSError:
    pass
try:
    os.mkdir("/tmp")
except OSError:
    pass
try:
    os.mkdir("/tmp/foo")
except OSError:
    pass
print(os.listdir("/tmp"))
try:
    os.rename("/tmp/foo", "/tmp/foo/bar")
except OSError as e:
    print(e)
print(os.listdir("/tmp"))
os.rename("/tmp/foo", "/tmp/bar")
print(os.listdir("/tmp"))
os.rename("/tmp/bar", "/tmp/barfoo")
print(os.listdir("/tmp"))
os.rename("/tmp/barfoo", "/tmp/barfoo/hello/world")
print(os.listdir("/tmp"))

[dhalbert]

Looks good! i2cslave is still on for M0 Express boards, so you could turn it off to make more room next time.