* nick/ssh/fix-process-leak/OTP-8807:
  Fix race condition when terminating a connection.
  fix process leak in ssh_system_sup (dynamicaly created childs where not cleaned up)

The ssh_system_sup supervisor supervises one ssh_subsystem_sup process for
every client connection. There was no functionality to free resources
(terminate_child/ delete_child) when a client connection was closed.
Which lead to one ssh_subsystem_sup and one ssh_channel_sup process left over.

This commit adds ssh_system_sup:stop_subsystem/2 and code that calls it
in ssh_connection_manager:terminate/2.

* maint-r13:
  snmp: Patch 1130
  inets: Patch 1129
  ssh: Patch 1127
  ssh: Patch 1126

Conflicts:
	lib/inets/doc/src/notes.xml
	lib/inets/src/inets_app/inets.appup.src
	lib/inets/vsn.mk
	lib/snmp/vsn.mk
	lib/ssh/doc/src/notes.xml
	lib/ssh/src/ssh.appup.src
	lib/ssh/vsn.mk

    OTP-8735  SSH in some cases generated a crash report when a channel
              was closed in a normal way.

    OTP-8714  SSH in some cases terminated channels with reason normal
              when it should have been shutdown.

    OTP-8550  The function ssh:connect/4 was not exported.

    OTP-8644  Aligned error message with used version (SSH_FX_FAILURE
              vs SSH_FX_NOT_A_DIRECTORY, the latter introduced in version
              6).

    OTP-8645  Resolved race condition when another connection is started
              before a channel is opened in the first connection.

    OTP-8535  The configuration parameter ip_v6_disabled is now available,
              which makes it possible for the user to alter the IP version
              SSH shall use.

    OTP-8534  The ssh_connection:send operation now accepts infinity as
              timeout.

    OTP-8524  The connection handler now include stack traces when a channel
              message is not handled correctly.

Some application's vsn.mk files contained a list of the ticket
numbers fixed in each version.

Since that information can be obtained from the notes.xml file or
from the merge commits in the git repository (provided that the
branch name includes the ticket number), there is no reason to
manually maintain that information in the vsn.mk files.