do_polling for efficiency

Also added setting timeout value to one second for precise and
refactoring timeout handling

module

Changes in b10-stats_test.py:
 - added deeply checking statistics values of each of module and
   instance

 - added stats_server.shutdown() at the end of the test_config method.
   Because the running stats_server was never shut down even after
   stats_server.run() was invoked.

Changes in test_utils.py:
 - Changed the way of invoking multiple auth instances just for efficiency

the second argument of the the 'update_statistics_data' method

Instead of PID(Process Id) used in previous version of stats codes,
'mid' (module id) is used for identifying multiple instances of same
module. 'lname' of CC-session in stats codes is assigned to it.

The description about 'set' command was removed from the manpages, and
A 'poll-interval' config item was introduced into the manpages. Also
the implement, the testcases and specification related to the set
command were removed from source codes and the specfile.

one while stats module is working
also system test of statistics is disabled until codes of both
Boss(#2137) and Auth(#2138) due to their dependencies

* change of b10-config dbfile
* update specfile of MockBoss
* invoking three extra Auth modules at a time in the BaseModules class
* implement 'getstats' command in each mock module

since stats doesn't request only boss but request every module

Mock boss

Stats module asks cfgmgr components of boss config. This test db file
contains test components of boss. Data of components are assumed to be
used only for counting number of multi intances. Here the module of
the multi instances is Auth.

Because that is already done while creating a BaseModules object at the setUp
method

 - update last_update_time when initially updating statistics of stats
 - strict validation check of poll-interval
 - move the code requesting to boss inside of the main loop

This is a time interval to requesting statistics data to each module.

As suggested by cppcheck.

This fixes a build failure on the build bots.

Conflicts:
	src/lib/dhcp/iface_mgr.cc

* Newlines have been added to the default values where it returns
  "Unknown" to preserve formatting.

* If a command fails, a failure message is returned instead of
  "Unknown".

changed or added some docbook formatting tags

slight grammar or punctuation changes

some clarifications or rewording; minor explanations.

removed some superfluous content or examples or simplified.

This was not reviewed.