Default network-stream-use-client-certificates to nil

* lisp/net/network-stream.el (network-stream-use-client-certificates):
Default to nil.
(open-network-stream): Adapt description to new default of
network-stream-use-client-certificates.

* etc/NEWS: network-stream-use-client-certificates defaults to nil
now.

* doc/lispref/processes.texi (Network): Flip
network-stream-use-client-certificates description.

* doc/misc/auth.texi (Help for users): Mention
network-stream-use-client-certificates.
1 job for master in 60 minutes and 5 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #4332
test-all

01:00:05

 
Name Stage Failure
failed
test-all Test
Makefile:319: recipe for target 'check-doit' failed
make[2]: Leaving directory '/builds/emacs/emacs/test'
make[2]: *** [check-doit] Error 1
make[1]: *** [check-expensive] Error 2
Makefile:294: recipe for target 'check-expensive' failed
make[1]: Leaving directory '/builds/emacs/emacs/test'
make: *** [check-expensive] Error 2
Makefile:959: recipe for target 'check-expensive' failed
ERROR: Job failed: exit code 1