MemMapFs Remove file panics

[acabarbaye]

I am using 1.9.5
when trying to remove a file such as /tmp/test-973171232/testDir/test-129751122.test using MemMapFS, I am getting a panic
panic: parent of /tmp/test-973171232/testDir/test-129751122.test is nil coming from unRegisterWithParent (

afero/memmap.go

Line 72 in d92c300

log.Panic("parent of ", f.Name(), " is nil")

).
The same used to be possible in previous versions and therefore, this looks like a regression.