MFC r311233,r311377:

r311233:

Fix Coverity issues

• Initialize .sun_len before passing it to strlcpy and bind.
• Close fd on error

CID: 978283, 979581

r311377:

Redo fix for CID 979581

The previous change was flawed in terms of how it calculated the
buffer length for the sockaddr_un object. Use SUN_LEN where
appropriate and mute the Coverity complaint by using memset(.., 0, ..)
to zero out the entire structure instead of setting .sun_len to a bogus
value and strlcpy'ing in the contents of argv[1].

SUN_LEN is now being passed to bind(2) as well. For some odd reason
this wasn't flagged as a bug with Coverity.