Clean-up shell run and run_subcommand methods

Remove else branch of try-catch block since
it is never executed.

Get rid of passing result to shell clean-up function
since it is not used.

Change-Id: I9360d1e27fc203672ba0511b58172f5c776bdfb6
Silence iso8601 debug messages in verbose mode

In verbose mode, iso8601 package produces the following useless debug
messages:

DEBUG: iso8601.iso8601 Got u'2014' for 'year' with default None
DEBUG: iso8601.iso8601 Got u'09' for 'monthdash' with default 1
DEBUG: iso8601.iso8601 Got 9 for 'month' with default 9
DEBUG: iso8601.iso8601 Got u'14' for 'daydash' with default 1
DEBUG: iso8601.iso8601 Got 14 for 'day' with default 14
DEBUG: iso8601.iso8601 Got u'16' for 'hour' with default None
DEBUG: iso8601.iso8601 Got u'31' for 'minute' with default None
DEBUG: iso8601.iso8601 Got u'23' for 'second' with default None

This change silences them.

Change-Id: Ibd0c5bb48b1ab86aaee2c8cb4f27b7e5fa8b4bef
Allow to specify policy by name in firewall-update

Currently only firewall policy ids are supported in firewall-update,
this change allows to use firewall policy names in firewall-update:

  neutron firewall-update my-firewall --policy my-new-policy

DocImpact
Change-Id: I84ad97fc7f1f2e81cad98497d4d983606fa03077
Merge "Silence iso8601 debug messages in verbose mode"
Merge "Clean-up shell run and run_subcommand methods"
Merge "Allow to specify policy by name in firewall-update"