os: should not have auto-generated signal lists

[rsc]

they expose too much about syscall

[robpike]

Comment 1:

Owner changed to builder@golang.org.

[bradfitz]

Comment 2:

http://golang.org/cl/5574078

Owner changed to @bradfitz.

Status changed to Started.

[bradfitz]

Comment 3:

This issue was closed by revision a3fdd6e.

Status changed to Fixed.