Use the right NID when putting a method in the store

When we attempt to fetch a method with a given NID we will ask the
providers for it if we don't already know about it. During that process
we may be told about other methods with a different NID. We need to
make sure we don't confuse the two.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8541)