openssl: genpkey not working properly with (external) provider signature algorithm

This issue pertains to master and can be reproduced (using oqsprovider) running the following:

LD_LIBRARY_PATH=.local/lib .local/bin/openssl genpkey -provider-path _build/oqsprov  -provider oqsprovider -algorithm dilithium2

never returns but has the CPU spinning at 100%.

With parameters arranged differently, an equally unexpected error is reported:

>LD_LIBRARY_PATH=.local/lib .local/bin/openssl genpkey -algorithm dilithium2 -provider-path _build/oqsprov  -provider oqsprovider -algorithm dilithium2 
Error initializing dilithium2 context
C091DB79F37F0000:error:0308010C:digital envelope routines:inner_evp_generic_fetch:unsupported:crypto/evp/evp_fetch.c:331:Global default library context, Algorithm (dilithium2 : 0), Properties (<null>)