Remove the old "SecureRandom" service, formerly used by get_random_bytes()

Remove the old "SecureRandom" service, formerly used by get_random_bytes()     

"SecureRandom" is no longer used, since it was replaced by a new
get_random_bytes() syscall.

 * Remove the RNG NaClDesc type.  Remove DescWrapper's constructor for
   this descriptor type.

 * Remove the code that registers an RNG NaClDesc with the name
   service as "SecureRandom".  Since this turns
   NaClDefaultNameServiceInit() into a no-op, remove that too.

 * Update a test that was checking SecureRandom as an example of a
   service.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3864
TEST= compile + run_nameservice_test

Committed: http://src.chromium.org/viewvc/native_client?view=rev&revision=13715

[Mark Seaborn, 2014-09-05 23:47:00]

mseaborn@chromium.org changed reviewers:
+ mcgrathr@chromium.org

[Roland McGrath, 2014-09-09 17:59:40]

lgtm

[Mark Seaborn, 2014-09-09 18:02:45]

The CQ bit was checked by mseaborn@chromium.org

[commit-bot: I haz the power, 2014-09-09 18:03:46]

CQ is trying da patch. Follow status at
 https://nativeclient-status.appspot.com/cq/mseaborn@chromium.org/550523002/1

[commit-bot: I haz the power, 2014-09-09 18:04:10]

Committed patchset #1 (id:1) as 13715