Eina Log: don't remove a domain from env var list on the first register

Eina Log: don't remove a domain from env var list on the first register

Let say you pass a log level 4 for a domain on env var.

So if you, for some reason, register a domain, unregister it, and register
it again, the log level will be set as 1 instead of 4.
And you'll miss info and debug msgs...

Now only remove this information when cleaning pending list,
on eina_log_shutdown().

git-svn-id: http://svn.enlightenment.org/svn/e/trunk/eina@73380 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33