Sync parts of X509_STORE_get_by_subject() with OpenSSL

Sync parts of X509_STORE_get_by_subject() with OpenSSL

Initialize stmp.type and stmp.data.ptr so that a user-defined lookup
method need not take responsibility of initializing those. Get rid of
current_method, which was never really used. Stop potentially returning
a negative value since most callers assume Boolean return values already.

In addition, garbage collect the pointless j variable.

ok jsing