ofconfig: add commit and discard_changes operation support

They are necessary for switches that don't support the feature of
modifying 'running' configuration directly; instead, needs to modify
'candidate' configuration and then commit (or discard).

Also fix do_get method's comment typo.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
of13/14: fix OFPFMFC_TABLE_FULL typo

Reported-by: Morgan Yang <Morgan.Yang@radisys.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
rename neutron agent from "ofswitch" to "ofagent"

suggested by some openstack folks.
see https://review.openstack.org/#/c/71791

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
test_add_flow_v12_actions: fix a typo

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
sw test tool: make the message receiving part independent as a class

the test methods which are in the OfTester class (e.g. _test_flow_install()) are due to be divided and stored in several classes by this patch series.
as a result, OfTester._wait() will be called from several classes.
for ease to reference from each class, the part that receives messages becomes independent as a class, and it holds as a single instance in the module.

the Waiter class, the part that receives messages, takes the following on from the OfTester class:

  - the method that waits for the messages
  - the methods that handle received messages
  - the variables that are used by the above methods
test