erasure-code: ErasureCodeLrc update default values to string

erasure-code: ErasureCodeLrc update default values to string

Update the ErasureCodeLrc::init function to use string default values
and update the profile accordingly.

If the k,m,l values are set and generate mappings and layers entries,
those are not stored in the profile. The details of what k,m,l create
are private and not exposed to the caller.

http://tracker.ceph.com/issues/9589 Fixes: #9589

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