erasure-code: test LRC pool, profile and crush ruleset

erasure-code: test LRC pool, profile and crush ruleset

Using the command line to create an LRC pool validates that the plugin
can be loaded and the ruleset created immediately after the crush table
is populated with the default rulesets.

Add a test that takes out the first OSD holding data for an object and
checks the recovery is effective by retrieving the object content and
checking it is as expected.

Signed-off-by: Loic Dachary <loic@dachary.org>