ScanCode should not consider scanning devices and special files

[JonoYang]

This is a regression. For example, running scancode -l --json-pp - /sys/devices/ on a Debian box should not even attempt to scan the files.

[pombredanne]

Thanks. That's a regression introduced with the new codebase model.

[adityaviki]

@pombredanne

What do you mean by "regression"? also, what type of file should not be considered for scanning?

[pombredanne]

@adityaviki a "regression" is a general term for something that used to work and no longer works (it did "regress"). Here I am pretty sure that we did not attempt in the past to scan any character device file, FIFO and similar.
At least that must have been the case in v1.0
That said, we want to skip these: FIFO, character device files, symlinks,

For instance you can see that the code in https://github.com/nexB/scancode-toolkit/blob/v1.2.0/src/commoncode/fileutils.py#L250 was skipping these special files as fileutils.walk() was used then by cli.py indirectly