Add ignore_retcode argument to cmd.run* funcs
Add ignore_retcode argument to cmd.run* funcs

As of 2014.1.0, all cmd.run* funcs will log stderr to the minion log as
well as a notification that the command failed, when the return code is
nonzero. However, there are instances in which you expect to have a
nonzero return code, which don't constitute an error. See
https://github.com/saltstack/salt/issues/11154#issuecomment-37590775 for
more information.

This commit adds an ignore_retcode argument which, if True, will
suppress the potentially misleading log entries saying that the command
failed.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt