erasure-code: verify the profile content matches get_profile()

erasure-code: verify the profile content matches get_profile()

The profile stored by the plugin may be different from the one set by
the user: it includes defaults. When the plugin is initialized, the
profile is modified to include the default values. Verify that the
modified profile matches what the get_profile() method returns, to guard
against inconsistencies from the erasure code plugin implementation.

http://tracker.ceph.com/issues/11663 Fixes: #11663

Signed-off-by: Loic Dachary <ldachary@redhat.com>