Trim whitespaces at the end of lines. Use the commit to record

Trim whitespaces at the end of lines. Use the commit to record
proper log message for r216150.

MFC after:	1 week

If unix socket has a unix socket attached as the rights that has a
unix socket attached as the rights that has a unix socket attached as
the rights ... Kernel may overflow the stack on attempt to close such
socket.

Only close the rights file in the context of the current close if the
file is not unix domain socket. Otherwise, postpone the work to
taskqueue, preventing unlimited recursion.

The pass of the unix domain sockets over the SCM_RIGHTS message
control is not widely used, and more, the close of the socket with
still attached rights is mostly an application failure. The change
should not affect the performance of typical users of SCM_RIGHTS.

Reviewed by:	jeff, rwatson